What is one of the most important beliefs in Hinduism?
O
A. The belief that people are reincarnated after death
O
B. The belief that human actions are ultimately unimportant
) C. The belief that there is only one god who must be obeyed
O
D. The belief that members of all social classes are equal

A.  The belief that people are reincarnated after death

Explanation:

Hinduism is very fascinating and one core belief they observe is reincarnation.

The other options are false because hindus do belief that human actions are important (law of karma).

Mainstream hinduism is seen as polytheistic (i.e. many gods) however, there's also a saying in hinduism that everything originated from one god, but for your question option C should be false as well.

D is false as well because people were divided into different classes which I do not think is necessarily part of hinduism because it is what happened in the culture at that time but somehow got fused with the religion.

Overall A is the best option.

can you post options so i can ?