Careful and cautious are synonyms (they mean the same thing). Boastful and arrogant are also synonyms. The answer is not (choice b) because humble means the opposite of boastful. The answer is not choice c or d because neither means the same as boastful.
A pen is a tool used by a poet. A needle is a tool used by a tailor. The answer is not choice a, b, or c because none is a person and therefore cannot complete the analogy.
EXAMIANS