What was Martin Luther's main gripe with the Catholic Church? According to Luther, how does a person gain salvation?

His central teachings, that the Bible is the central source of religious authority and that salvation is reached through faith and not deeds, shaped the core of Protestantism. Although Luther was critical of the Catholic Church, he distanced himself from the radical successors who took up his mantle.

Explanation:

i would say your answer is a)

sorry if im wrong