To people who believed in the Mandate of Heaven, when was it all right to 2 point
overthrow an emperor?
A. never at any time
B. when he ruled badly
C. when he became unpopular
D. when citizens wanted a change

B. When he ruled badly.

Explanation:

Chinese emperors were said to rule with the mandate of Heaven. They were also expected to rule with justice and be virtuous. But when a ruler started to act unjustly, when there´s was rampant corruption, and when rule turned uncapable to solve problems and people´s suffering, when tyranny became unsufferable, so there were revolts or even massive peasant uprisings that led to the overthrowing of  en emperor. Many dynasties fell like that. In such cases, new rulers took over and it was said that Heaven had withdrawn its favor from the old ruler and conferred it upon  a new emperor.