The correct answer is D. Both (A) and (B).
Lac is a resinous secretion produced by lac insects. It is used in a variety of products, including varnishes, paints, and shellac. The lac industry is developed in Gaya and Purnea districts of Bihar.
Gaya is a city in the Indian state of Bihar. It is the headquarters of Gaya district and the Gaya division. The city is located on the banks of the Phalgu River, about 100 kilometers (62 mi) south of Patna, the state capital. Gaya is a major pilgrimage site for Hindus and Buddhists. The city is home to the Mahabodhi Temple, a UNESCO World Heritage Site.
Purnia is a city in the Indian state of Bihar. It is the headquarters of Purnia district and the Purnia division. The city is located on the banks of the Kosi River, about 300 kilometers (190 mi) north of Patna, the state capital. Purnia is a major agricultural and commercial center. The city is also home to a number of educational institutions.
The lac industry is a major source of employment in Gaya and Purnea districts. The industry is responsible for the production of a variety of products, including varnishes, paints, and shellac. The lac industry is a significant contributor to the economy of Bihar.