How to null check?

I am working to remake PvZ in Unity for practice and I believe I am getting this error because I am not null checking line 33 but I can not figure out how to nullcheck it.


I am getting this error in Unity

"NullReferenceException: Object reference not set to an instance of an object
Peashooter.FireBullet () (at Assets/Scripts/Peashooter.cs:33)"


I am sure this is a simple solution that I am looking over on Google but I appreciate any help. Thanks!

Code (CSharp):

1. private void FireBullet()
2.     {
3.        if (Mathf.Abs(transform.position.x - FindObjectOfType<Zombie>().transform.position.x) < RangeToShoot)
4.         {
5.            
6.             RaycastHit2D[] hits = Physics2D.RaycastAll(transform.position, Vector2.right * 12);
7.             Debug.Log("Print!");
8.  
9.            
10.  
11.                 foreach (RaycastHit2D hit in hits)
12.                 {
13.                     if (hit.collider != null &&
14.                         hit.collider.gameObject.tag == "Zombie")
15.  
16.                     {
17.                         Instantiate(Bullet,
18.                           FirePoint.transform.position,
19.                             Quaternion.identity);
20.                     }
21.  
22.                 }
23.              }
24.     }