drag and drop in specific area Unity

I want to implement a drag and drop of an image but in spesific area as this picture

so when someone drag for example the picture of the "orange" and drop it on the area "Apple" it will not work and the picture "oragne" come back to its place , but if he drop it on the area "orange" it will work ..

I have a code that drag and drop an image in any place which is not my aim , can someone help me to add some code to drop the right image on the right area please ??

DragHandeler.cs

 using UnityEngine;
 using System.Collections;
 using UnityEngine.EventSystems;
 
 public class DragHandeler : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler {
 public static GameObject itemBeingDraged;
 Vector3 startPosition;
 Transform startParent;
 
 #region IBeginDragHandler implementation
 public void OnBeginDrag (PointerEventData eventData)
 {
     itemBeingDraged = gameObject;
     startPosition = transform.position;
     startParent = transform.parent;
     GetComponent<CanvasGroup>().blocksRaycasts = false;
 }
 #endregion
 
 
 #region IDragHandler implementation
 public void OnDrag (PointerEventData eventData)
 {
     transform.position = Input.mousePosition;
 }
 #endregion
 
 #region IEndDragHandler implementation
 
 public void OnEndDrag (PointerEventData eventData)
 {
     itemBeingDraged = null;
     GetComponent<CanvasGroup>().blocksRaycasts = true;
     if (transform.parent != startParent) {
         transform.position = startPosition;
     }
 }
 
 #endregion
 }

inventory.cs

 using UnityEngine;
 using System.Collections;
 using UnityEngine.EventSystems;
 using UnityEngine.UI;
 
 public class inventory : MonoBehaviour, IHasChanged {
 
 [SerializeField] Transform slots;
 [SerializeField] Text inventoryText;
 
 // Use this for initialization
 void Start () {
     HasChanged ();
 }
 
 #region IHasChanged implementation
 
 public void HasChanged ()
 {
     System.Text.StringBuilder builder = new System.Text.StringBuilder();
     builder.Append (" - ");
     foreach (Transform slotTransform in slots) {
         GameObject item = slotTransform.GetComponent<Slot>().item;
         if (item){
             builder.Append (item.name);
             builder.Append (" - ");
         }
     }
     inventoryText.text = builder.ToString ();
 }
 
 #endregion
 }
 
 namespace UnityEngine.EventSystems {
 public interface IHasChanged : IEventSystemHandler {
     void HasChanged();
 }
 }

Slot.cs

 using UnityEngine;
 using System.Collections;
 using UnityEngine.EventSystems;
 
 public class Slot : MonoBehaviour, IDropHandler {
     public GameObject item {
         get{
             if(transform.childCount>0){
                 return transform.GetChild(0).gameObject;
             }
             return null;
         }
 }
 
 #region IDropHandler implementation
 
 public void OnDrop (PointerEventData eventData)
 {
     if (!item) {
         DragHandeler.itemBeingDraged.transform.SetParent (transform);
         ExecuteEvents.ExecuteHierarchy<IHasChanged>(gameObject,null,(x,y) => x.HasChanged ());
     }
 }
 
 #endregion
 }

Thanx ^^