A word to describe giving a B.S. answer with total self-confidence?

Question

When you've completely made-up an answer to a question, but you've said it with such self-confidence that everyone assumes you know what you are talking about.

Answer 1

bravado?

or brazen

Answer 2

John's response to the teacher, though based on a tissue of lies, was said with such total conviction that the teacher bought it!