Which of the following best explains the process illustrated in the image? States increasingly relied on slave soldiers to establish large empires.

States increasingly relied on slave soldiers to establish large empires.
A

The invention of the stirrup allowed expanding states to use cavalry more effectively.

The invention of the stirrup allowed expanding states to use cavalry more effectively.
B

The development of new types of armor reduced casualties and allowed states to expand faster than before.

The development of new types of armor reduced casualties and allowed states to expand faster than before.
C

D States used gunpowder weapons to establish large empires.