Achievements of the Gupta Empire A. Developed advanced medical treatments
B. Formed an alliance with Alexander the Great
C. Built the first Hindu temples
D. Captured all Mauryan territory

i believe the answer is, C.

Explanation:

The Gupta Dynasty, were the first to build the Hindu temples which evolved from the earlier tradition of rock-cut shrines. Adorned with towers and elaborate carvings, these temples were often dedicated to all the Hindu gods.

the melanesian is basically practicing magic.

although the crusades failed to capture jerusalem, they had several major impacts on western europe. they increased the authority of the king: sometimes nobles died in battle without leaving an heir in which case the king got their land. kings passed taxes to pay for the crusades.