Answer:
A. . Both practices were serious sins that went against Catholic teaching.
Step-by-step explanation:
At that time, indulgences is considered as a 'remissions' from previous sins. Christians believe that God is the only one that has the right to forgive the sins. This is why selling/buying indulgences are considered as an act of sin.
By monetizing indulgences, many Catholics believed that The churches has put their way in the position where they believe they can act on God's behalf to erase other people's sins.