Final answer:
The Brahmans were at the top of the caste system as they were priests with significant religious knowledge and authority, helping to maintain the divine social order.
Step-by-step explanation:
The Brahmans were at the top of the caste system because they were priests who exerted authority by virtue of their knowledge of sacrificial rituals and their role as guardians of the Vedic traditions. In Hindu society, the caste system was strongly tied to religious beliefs and was seen to ensure that people performed their proper role in life according to their actions in past lives. This divine social order was believed to maintain cosmic justice and was ordained by the gods; thus, the Brahmans enjoyed a privileged position closest to the deities.
Answering the student's question, the correct option is A. Brahmans are priests and were at the top to be closest to the gods.