What’s the maximum length a TrueView video ad can be?

A) 1 minute, 30 seconds
B) There isn’t a time limit
C) 30 seconds
D) 7 minutes

The correct answer is:

B) There isn’t a time limit

Explanation: You can also run videos longer than 30 seconds. You can try longer product demos, customer testimonials, or a how-to video demonstrating your product in action. But you will be charged if a viewer watches 30 seconds of your video (or the duration if it’s shorter than 30 seconds) or interacts with your video, whichever comes first.

Read more here: https://support.google.com/adwords/answer/2375464?hl=en