Audio not playing on activation

My previous audio stops when I press the button, but the new source does not start. Any help is is highly appreciated.

var pressed : boolean = false;
var AudioA : GameObject;
var AudioB : GameObject;
var AudioC : GameObject;
var AudioD : GameObject;

function OnMouseDown () {

audio.Play();

if (pressed == true) {
AudioA.active = false;
AudioB.active = true;
AudioC.active = false;
AudioD.active = false;
	}
}

function OnMouseUp () {

pressed = true;
renderer.material.color = Color.red; 
audio.Play();

}

You’re confusing things: this script only affects its own sound, not the sounds associated to AudioA/B/C/D (unless it’s attached to one of them). If you want to control the AudioA/B/C/D objects, use their audio properties instead - for instance:

AudioA.audio.Play();

But I honestly don’t understand what you’re trying to do: do you need to activate/deactivate objects, or it was simply a way to stop/play the sound?