Muga Silk, a unique variety of silk, is produced in:

The correct answer is: a) Assam.

Muga silk is a unique variety of silk produced by the Antheraea assamensis moth, which is found in the forests of Assam, India. It is one of the most expensive silks in the world, and is known for its fineness, luster, and strength. Muga silk is used to make a variety of products, including sarees, scarves, and shawls.

The other options are incorrect because they are not the states in India where Muga silk is produced. Manipur is a state in northeastern India, Meghalaya is a state in northeastern India, and Arunachal Pradesh is a state in northeastern India. None of these states are known for the production of Muga silk.