How to play Audio Once if enemy has enterd a trigger

Hi Guys. trying to make my zombie scream if he enters my trigger. This is the script i have came up with

var target : Collider;
private var triggered : boolean = false;

function OnTriggerEnter(collision : Collider)
 if (collision !=target)

triggered = true; 

How do i tell it what audio to play. My sound is called “ZombieScream”

also my zombie is taged Enemy if thats any help.

You want to use audio.PlayOneShot(clip : AudioClip);