Why did the islamic world suffer hardship during the 1200s and 1300s?

a.
christian soldiers of the byzantine empire forced muslims under their control to accept christianity or face death.

b.
mongol armies rode out of central asia to invade and conquer first one part and then another part of the muslim world.

c.
muslim tyrants kept their subjects in serfdom and poverty.

d.
western european kings sent armies to retake jerusalem and capture as many muslims as possible to use as slaves.