The correct answer is: a) Bay of Bengal.
The majority of rivers in Bihar drain into the Bay of Bengal. The rivers in Bihar are part of the Ganges River system, which is the largest river system in India. The Ganges River flows through the states of Uttarakhand, Uttar Pradesh, Bihar, Jharkhand, West Bengal, and Bangladesh. The Ganges River is a sacred river for Hindus, and it is a major source of water for irrigation and drinking water.
The other options are incorrect. Option b) is incorrect because the Arabian Sea is located to the west of India. Option c) is incorrect because the Indian Ocean is located to the south of India. Option d) is incorrect because the Himalayan glaciers are located in the Himalayas, which are located to the north of India.
The rivers in Bihar are important for the economy of the state. The rivers are used for irrigation, drinking water, and transportation. The rivers are also a popular tourist destination.