Buddhism and Jainism Gained Popularity in the Late Vedic Period

Buddhism and Jainism gained popularity in the late Vedic period because

A) they offered an alternative to the ritualistic, exclusive religion of the Brahmins.
B) there was more trade with China, and missionaries were sent.
C) naturalistic religions were felt to be more in keeping with the sky-gods of old.
D) they reinforced pre-existing social norms.
E) each posited polygamy as an option.