Question

What groups were most vocal in their opposition to rock n’ roll?

Answer 1

Various religious groups were most vocal in their opposition to rock n’ roll.

Answer 2

It was probably various religious, Christian groups who opposed rock n' roll. They believed that this music inspired violence and rebellion, and was devoted to the Devil himself. They thought that rock music was against God, and a form of blasphemy, and thus they tried their very best to make it go away. Obviously, they were unsuccessful.