Answer:
D. Sale of Indulgences.
Step-by-step explanation:
Indulgences, according to the Catholic Church in the past, is the way of reducing the amount of punishment or judgment that a person is supposed to get after death. These punishments are a result of the sins committed during one's lifetime.
The sale of indulgences was a common practice that saw clergymen and bankers' agents selling such 'pardons' to people. And the practice of buying such pardons was also a huge 'gain' for the people who would commit sin and then get pardoned through indulgences.
Thus, the correct term depicted in the image is the selling of indulgences.