Which of the Following Was a Consequence of the Collapse

Which of the following was a consequence of the collapse of the Zhou dynasty?

A) Rivalry among competing rulers promoted and accelerated military and other technological innovations.
B) China fell into an extended period of economic collapse and population implosion.
C) Foreign powers invaded the remnants of the Zhou dynasty, and Chinese culture was temporarily suppressed.
D) Smaller rulers entered into a relative period of peace in order to reestablish stability in urban centers as well as in the countryside.