Acommercial for a tutoring center that shows a grade school-aged boy blushing with embarrassment when his teacher calls on him to read aloud in class. which identifies a persuasive technique used by the ad and explains its effect on viewer emotions?

The ad uses two aspects that help you empathize with the boy.

First that lots of people have problems with speaking in public. Shaking, blushing and sweating are usual consequences of this issue. Blushing is the "cutest" of these symtoms, and this, happening with a school-aged boy helps you relate.

Which leads to the next aspect: everybody in the target of the ad has already been a child, and all the issues and memories that it implies. A 50 year old politician blushing before a speech would not be as persuasive...

Therefore, in the three-way persuasive techniques list (along with Ethos and Logos), the "Pathos" is the one mostly used by the ad.

In the longer list, "appeals" and 'cliches" are clearly used.

faith or loyalty when pledged in a solemn agreement or undertaking.