"You are the bomb!" is an informal slang expression used to praise someone. It means the person is excellent, outstanding, or highly impressive, not literally explosive or destructive. The phrase became popular casual speech to express strong admiration.
Option 1, a bad temper, confuses the idiom with unrelated expressions about anger, such as someone being a ticking time bomb, which is a different idiom with a different meaning. Option 2 and option 4 both take the word bomb literally, treating it as a weapon or something dangerous, but slang idioms often use a word in a sense completely detached from its literal meaning, and that is exactly the case here.
Since the informal, complimentary sense is the intended one, option 3, you are exceptional and or wonderful, is correct.