How Did the First Zhou Rulers Justify Their Overthrow of the Shang

How did the first Zhou rulers justify their overthrow of the Shang?

A) By maintaining strict surveillance over the people.
B) By maintaining strict control over both weapons and religious objects.
C) By convincing the people that they ruled through a mandate from heaven.
D) By keeping most of the population illiterate and tied to the land.
E) By monopolizing the trade in metals, salt, and silks.