Answer:
b. conquer Greece
Step-by-step explanation:
Interestingly, Xerxes's own statement shows that his goal was to conquer the Greek empire. Recall he said, "I may obtain vengeance from the Athenians," this shows he had some grievances with Greece whose capital city was Athens.
Darius, Xerxes father died without achieving his goal of conquering the entire greek empire, so as his son, Xerxes felt a desire to attempt doing what his father couldn't fully accomplish.