Given below are four jumbled sentences. Select the option that gives their correct order.

A. According to him the upper caste Brahmins of the society had started this policy as they detested Buddhism.

B. R. Ambedkar who came from a social group that was regarded as untouchable believed that this practice existed in the ancient India.

C. Untouchability is a heinous practice and it has been outlawed in India.

D. Different scholars have refuted this theory later.