The correct answer is (a) Karnataka.
Karnataka is the only state in India that has diamond mines. The mines are located in the Chitradurga district, about 200 kilometers from Bangalore. The diamonds found in Karnataka are of high quality and are used in jewelry all over the world.
The other options are incorrect because they are not states in India that have diamond mines.
(b) Uttar Pradesh is a state in northern India. It is the most populous state in India, with a population of over 200 million people. Uttar Pradesh is not known for its diamond mines.
(c) Madhya Pradesh is a state in central India. It is the second most populous state in India, with a population of over 100 million people. Madhya Pradesh is not known for its diamond mines.
(d) Tamil Nadu is a state in southern India. It is the sixth most populous state in India, with a population of over 70 million people. Tamil Nadu is not known for its diamond mines.