Concept:The expression “show one’s true colours” means to reveal what a person is really like, especially when that nature was previously hidden.
Explanation:The prefect was elected, and soon after that, he “showed his true colours.”
This idiom does not refer to a speech, pride, or hard work.
It means his real character became visible.
Therefore, the phrase is best understood as revealing his genuine personality or intentions.
Answer:B. revealed his real character