OnClick Functions Not Appearing,OnClick Not Showing Public Functions

So I am brand new to unity, so I am watching tutorials on Zenva. Everything was going fine, I was even starting to understand coding a little. Then I started the navigating between menus video, and now I am stuck with the on click functions not appearing. I have copied his coding word for word and followed the directions to the letter. Yet none of the public functions are showing up. I have looked for the solution online, many on this site, yet none of them solve my problem. So, here is the code.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class MainMenuController : MonoBehaviour {
 
     void Start () {
     }
 
     public void StartGame(){
         Application.LoadLevel ("Gameplay");
     }
 
     public void HighscoreMenu(){
         Application.LoadLevel ("HighScore Scene");
     }
 
     public void StartGame(){
         Application.LoadLevel ("Options Menu");
     }
         
     public void QuitGame(){
         Application.Quit ();
     }
         
     public void MusicButton(){
         
     }
 }

This is word for word what he has in the video. All the functions I need to be public are. Here are screenshots of me attaching the script to an empty game object, then attaching said game object to the on click area and trying to find the functions.

Once again, I am brand new to unity and all its technical jargon. I have looked up other solutions to this problem and have either found fixes that I don't have problems for, i.e. public functions and script to game object, or contain technical jargon that flies so far over my head I don't even feel the wind as it sails by. So can someone please help me with the simplest terms possible to a problem that I can't figure out.