Bihar is a major milk-producing state in India, with a significant population of:

The correct answer is: b) Buffaloes.

Bihar is a major milk-producing state in India, with a significant population of buffaloes. Buffaloes are the main source of milk in Bihar, accounting for over 70% of the state’s milk production. The state has a large number of buffaloes, with over 10 million animals. Buffaloes are well-suited to the climate and conditions in Bihar, and they are able to produce high-quality milk. The state government has been promoting the development of the dairy sector in Bihar, and there are a number of dairy cooperatives and milk processing plants in the state.

The other options are incorrect because:

• Cows are not the main source of milk in Bihar. They account for only about 30% of the state’s milk production.
• Goats are not a major source of milk in Bihar. They account for only about 1% of the state’s milk production.
• Sheep are not a major source of milk in Bihar. They account for only about 0.1% of the state’s milk production.