What Was the Reaction of the Tang When the Rise

What was the reaction of the Tang when the rise of Islam threatened the Silk Road?

A) The Tang emperors expanded their military presence in Central Asia to protect trade and the lucrative taxes it produced.
B) The Tang dynasty found itself financially strapped and unable to support all of its military and political commitments.
C) Tang merchants instead focused on developing domestic markets between eastern and western China.
D) Tang merchants formed a "silk road by the sea" using southern Chinese ports.