A sericulture hub famous for silk production in Karnataka:

Ramanagara
Mysuru
Kolar
Tumakuru

The correct answer is B) Mysuru.

Mysuru is a city in the Indian state of Karnataka. It is the third most populous city in the state after Bangalore and Hubli-Dharwad. Mysuru is known for its palaces, temples, and gardens. It is also a major center for silk production.

The silk industry in Mysuru dates back to the 16th century. The city was ruled by the Wodeyar dynasty, who were patrons of the silk industry. The Wodeyars built several silk factories in Mysuru, and the city became a major center for silk production.

Today, Mysuru is home to several silk factories and cooperatives. The city is also a major exporter of silk. Mysuru silk is known for its high quality and its beautiful designs.

The other options are incorrect. Ramanagara is a district in the Indian state of Karnataka. Kolar is a district in the Indian state of Karnataka. Tumakuru is a district in the Indian state of Karnataka. These districts are not known for silk production.