In the context of the passage, the phrase “His vanity nearly cost him the race,” suggests that the dog:
A. Felt that the water was so refreshing, he had no choice but to bathe in it whether it lost him the race or not.
B. Intended to look his best and be his cleanest when he reached the palace, in order to honor the Emperor.
C. Forgot that he was in a race to reach the Emperor’s Palace until he saw the pig approaching the riverbank.
D. Prioritized his egotistical impulses over his desire to reach the Emperor’s Palace on time.