Buddhism and Jainism Gained Popularity in the Late Vedic Period

Buddhism and Jainism gained popularity in the late Vedic period because

A) they tapped into the wellspring of popular discontent with the status and ranking of Brahmins.
B) there was more trade going on with China and missionaries were sent.
C) naturalistic religions were felt to be more in keeping with the sky-gods of old.
D) they offered insight or enlightenment as a path to salvation instead of rituals.
E) each posited polygamy as an option.