The correct answer is - A. It grew out of the overlapping beliefs of different groups in India.
The origins and formation of the Hinduism can be traced to the time of the Aryan invasion in the Indian subcontinent. The old Dravidian beliefs, mixed with the newly arrived Aryan beliefs, created a new religion that had elements from both of them, but got modified in a specific unique way, thus giving birth to what we now know as Hinduism.