is this C# or js ?

I found the code on internet i want to use as a base and for learning as i want to make something similar to it.

The question is if i put code into js or C# folder i get errors on both so i dont know which one is it.

 public class HeldObject : MonoBehaviour {
 
     public bool IsColliding { get; private set; }
 
     private void OnCollisionEnter(Collision collision)
     {
         IsColliding = true;
     }
 
     private void OnTriggerStay(Collider other)
     {
         IsColliding = true;
     }
 
     private void OnCollisionExit(Collision collision)
     {
         IsColliding = false;
     }
 }
 
 
 public class PlayerPick : MonoBehaviour
 {
     // Maximum distance from the camera at which the object can be picked up
     public float MaxPickDistance;
     public float ThrowStrength = 10;
     public float HeldObjectFollowStrength = 50;
 
     private Player _player;
     private Camera _playerCam;
     private GameObject _pivot;
 
     private HeldObject _heldObject; // physical avatar
     private GameObject _heldBodyAvatar; // visual avatar
     private float _heldBodyAngularDrag;
 
     private RaycastHit? _raycast;
 
     private void Start()
     {
         _player = Player.Instance;
         _playerCam = Player.Camera;
         _pivot = Player.PickPivot;
     }
 
     private void Update()
     {
         Raycast();
         if (Input.GetKeyDown(KeyCode.E))
         {
             if (!_heldObject)
                 TakeObject();
             else
                 ReleaseObject();
         }
         HoldObject();
         if (Input.GetMouseButton(0) && _heldObject)
             ThrowObject();
     }
 
     private void Raycast()
     {
         _raycast = null;
         const int layerMask = 1 << 8;
         var raycastHits = Physics.RaycastAll(_playerCam.transform.position, _playerCam.transform.forward,
                                              MaxPickDistance, ~layerMask);
         foreach (var hit in raycastHits)
         {
             if (hit.collider == _player.collider || !hit.collider.rigidbody) // avoid colliding with the player object itself
                 continue;
             _raycast = hit;
         }
     }
 
     private void HoldObject()
     {
         if (!_heldObject)
             return;
         // Drag the physical avatar by changing its velocity
         _heldObject.rigidbody.velocity = HeldObjectFollowStrength * (_pivot.transform.position - _heldObject.transform.position);
         // When the physical avatar collides, we move the visual one to the same position. When this doesn't happen,
         // move the visuals back to the pivot point.
         _heldBodyAvatar.transform.position = _heldObject.IsColliding
             ? _heldObject.transform.position
             : _pivot.transform.position;
         // If the physical avatar is colliding with something, change visuals rotation to correspond
         if (_heldObject.IsColliding)
             _heldBodyAvatar.transform.rotation = _heldObject.transform.rotation;
     }
 
     private void TakeObject()
     {
         if (!_raycast.HasValue)
             return;
 
         var heldBody = _raycast.Value.rigidbody;
         heldBody.transform.position = _pivot.transform.position;
         heldBody.useGravity = false;
 
         _heldBodyAngularDrag = heldBody.angularDrag;
         heldBody.angularDrag = 1; // so that the object doesn't continue rotating after each collision
         heldBody.renderer.enabled = false;
         _heldObject = heldBody.gameObject.AddComponent<HeldObject>();
 
         _heldBodyAvatar = new GameObject("Held body avatar");
         _heldBodyAvatar.transform.parent = _playerCam.transform;
         _heldBodyAvatar.transform.position = _pivot.transform.position;
         _heldBodyAvatar.transform.rotation = heldBody.transform.rotation;
         _heldBodyAvatar.transform.localScale = heldBody.transform.localScale;
         _heldBodyAvatar.AddComponent<MeshFilter>().sharedMesh = heldBody.gameObject.GetComponent<MeshFilter>().sharedMesh;
         _heldBodyAvatar.AddComponent<MeshRenderer>().sharedMaterial = heldBody.gameObject.renderer.sharedMaterial;
 
         Physics.IgnoreCollision(heldBody.collider, Player.Controller, true);
     }
 
     private void ReleaseObject(Action onRelease = null)
     {
         Physics.IgnoreCollision(_heldObject.collider, Player.Controller, false);
         _heldObject.rigidbody.useGravity = true;
         _heldObject.rigidbody.angularDrag = _heldBodyAngularDrag;
         _heldObject.rigidbody.transform.position = _heldBodyAvatar.transform.position;
         _heldObject.rigidbody.transform.rotation = _heldBodyAvatar.transform.rotation;
         _heldObject.rigidbody.renderer.enabled = true;
         _heldBodyAvatar.renderer.enabled = false;
         Destroy(_heldObject);
         Destroy(_heldBodyAvatar);
         if (onRelease != null)
             onRelease();
         _heldObject = null;
     }
 
     private void ThrowObject()
     {
         ReleaseObject(() => _heldObject.rigidbody.AddForce(_playerCam.transform.forward * ThrowStrength, ForceMode.Impulse));
     }
 }