Explanation
The words CAREFUL and CAUTIOUS have a similar meaning, indicating the need for taking precautions and avoiding risks. Similarly, BOASTFUL is a word that means tending to brag or show off excessively.
So, the word that has a similar meaning to CAUTIOUS and is related to BOASTFUL is ARROGANT. Arrogance is characterized by overconfidence and a tendency to brag, just as boasting is.
Therefore, the correct answer is A: Arrogant.
