The true statement related to bio gas in the field of energy production in Rajasthan is -

• A. The implementation of biogas scheme was started in the state in 1981-82.
• B. Most of the biogas plants in the state have been set up in Udaipur.
• C. Cow dung, urine and other wastes are collected and put in biogas plants and fermented, which generates biogas.
• D. all of the above