Why Did the Pax Mongolica Come to an End

Why did the Pax Mongolica come to an end?

A) Conflict between rival trading groups increased and violence broke out.
B) The Mongols lost control of the Silk Road to the Chinese.
C) The Mongols began to push further West into Europe and war broke out.
D) The Mamluk sultanate of Egypt began attacking caravans on the Silk Road.
E) The Mongols converted to Eastern Orthodox Christianity and so closed the Silk Road to Western Roman Catholics.