Question

For the late 5th century AD invasions by nomadic Huns

Answer 1

The correct answer is A - reduced the power of the Guptas.

Huns invaded among other things the empire where Guptas reigned. They were able to overthrow them for some time, however, they were eventually driven out. 

In any case, this did reduce their power as it showed that they were not invincible and could be invaded and defeated by a foreign and conquering force such as the Huns.