Error - An Object Reference is Required to Access Non-Static Member

Please halp me fix this..."GameController.AddScore()"

using UnityEngine; using System.Collections;

public class DestroyScript : MonoBehaviour{ public GameController gc; public GameObject Explosion;

 void Start(){
     gc = GameObject.FindGameObjectWithTag ("Player").GetComponent<GameController>();
 }

 void OnTriggerEnter (Collider Other)
 {
     if(Other.tag == "Player")
     {
         Instantiate (Explosion,transform.position, transform.rotation);
         GameController.AddScore();
         Destroy(gameObject);
     }
 }

}