Stop and Resume audio from other view controller iOS AVPlayer

I have an app that plays sound when it loads. This happens in the AppDelegate.m file because the audio is used in most places. But I would like to pause the sound when the user clicks on the help menu because the help menu contains a help video and I do not want the sound to interfere. And when the user goes back to the main menu I want the sound to resume. Basically I would like to access the sound and perform things on it. How can I do this.

Thanks in advance!

AppDelegate.m:

- (void)applicationDidBecomeActive:(UIApplication *)application

{

NSURL *url = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@/AppMusic.mp3", [[NSBundle mainBundle] resourcePath]]];

NSError *error;

audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];

audioPlayer.numberOfLoops = INFINITY;

[audioPlayer play];

}