How best to reference a Game Object to perform a if mathematical condition is met?

Good morning everyone I am working on the "Create With Code" tutorial. I am in Challenge 3 of the
Prototype 3 This lesson is Balloons, Bombs, & Booleans Bonus 7: The Balloon can float too high

The bonus asks that

• Prevent the player from floating their balloon too high

Hint: Add a boolean to check if the balloon isLowEnough, then only allow the player to add upwards force if that boolean is true

So my thought was to create a isLowEnough variable then use this variable to check to see if its current Height of the player balloon is less than or equal to the height of the top of the Background object. I am confused on how best to reference the Background game object in my if statement on line 40 of my PlayerControllers.cs script so that I can stop the balloon from exceeding this value.
What is the best way to accomplish this?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class PlayerControllerX : MonoBehaviour
6. {
7.     public bool gameOver;
8.  
9.     public float floatForce;
10.     private float gravityModifier = 2.5f;
11.     private Rigidbody playerRb;
12.     public ParticleSystem explosionParticle;
13.     public ParticleSystem fireworksParticle;
14.  
15.     public bool isLowEnough;
16.     private float ballonHeight;
17.  
18.     private AudioSource playerAudio;
19.     public AudioClip moneySound;
20.     public AudioClip explodeSound;
21.  
22.  
23.     // Start is called before the first frame update
24.     void Start()
25.     {
26.         ballonHeight = gameObject.GetComponent<>
27.         playerRb = GetComponent<Rigidbody>();
28.         Physics.gravity *= gravityModifier;
29.         playerAudio = GetComponent<AudioSource>();
30.  
31.         // Apply a small upward force at the start of the game
32.         playerRb.AddForce(Vector3.up * 5, ForceMode.Impulse);
33.  
34.     }
35.  
36.     // Update is called once per frame
37.     void Update()
38.     {
39.         // While space is pressed and player is low enough, float up
40.         if (Input.GetKey(KeyCode.Space) && !gameOver && isLowEnough <= Transform.Background.position.y;
41.         {
42.             isLowEnough = true;
43.             playerRb.AddForce(Vector3.up * 1 * floatForce, ForceMode.Impulse);
44.         }
45.     }
46.  
47.     private void OnCollisionEnter(Collision other)
48.     {
49.         // if player collides with bomb, explode and set gameOver to true
50.         if (other.gameObject.CompareTag("Bomb"))
51.         {
52.             explosionParticle.Play();
53.             playerAudio.PlayOneShot(explodeSound, 1.0f);
54.             gameOver = true;
55.             Debug.Log("Game Over!");
56.             Destroy(other.gameObject);
57.         }
58.  
59.         // if player collides with money, fireworks
60.         else if (other.gameObject.CompareTag("Money"))
61.         {
62.             fireworksParticle.Play();
63.             playerAudio.PlayOneShot(moneySound, 1.0f);
64.             Destroy(other.gameObject);
65.  
66.         }
67.  
68.     }
69.  
70. }

 

So sorry I put this in this Forum my mistake.

 

i m getting same error in this challenge 3

 

same bro