Which audience lends itself best to an informal style? Your boss's boss

Your best friend

Your congressional representative

An older relative you don't know very well

Your best friend.

Explanation:

The general rule of thumb with informality is that you use it with people you know well. You probably don't know your boss's boss, and even then, respect is still expected, or your congressional representative, and it's even in the description with your older relative.

Most people would agree that you probably know your best friend pretty well, so they will be the best audience for an informal style.

b. failure at least that one seems the most negative out of all of the answers provided pls correct me if i'm wrong. : ))