Answer:
A. The selling of indulgences was a major cause of the Protestant Reformation.
Explanation:
It is known as Protestant Reformation to the Christian religious movement, initiated in Germany in the sixteenth century by Martin Luther, which led to a schism of the Catholic Church to give rise to numerous churches grouped under the denomination of Protestantism.
The Reformation had its origin in the criticisms and proposals with which various religious, thinkers and European politicians sought to cause a profound and widespread change in the customs and customs of the Catholic Church, in addition to denying the jurisdiction of the pope over all Christianity.
In particular, the Reformation rejected Catholic sacramental theology, which, according to Luther, allowed and justified practices such as the "sale of indulgences", a sequestration of the Gospel, which should be freely preached, and not sold.