What is the meaning of the idiom "to swallow something hook, line, and sinker"?

When you say, "to swallow something hook, line, and sinker" it means to completely fall for whatever was said or to completely believe what was told or presented. Usually, what was presented is a lie, and when the person is gullible enough to believe it, the phrase applies.

its confident and professional

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