The correct answer is: a) Morbi.
Morbi is a city in Gujarat, India, known for its brass parts manufacturing industry. The city is home to over 10,000 brass manufacturing units, which employ over 100,000 people. The brass parts manufactured in Morbi are exported to over 100 countries around the world.
Jamnagar is a city in Gujarat, India, known for its oil refineries and petrochemical industries. The city is home to the Jamnagar Refinery, which is the largest refinery in India and the second largest refinery in Asia. The Jamnagar Refinery is operated by the Indian Oil Corporation.
Rajkot is a city in Gujarat, India, known for its textiles and diamond industries. The city is home to over 100 textile mills and over 100 diamond polishing units. The textiles manufactured in Rajkot are exported to over 100 countries around the world. The diamonds polished in Rajkot are exported to over 50 countries around the world.
Vapi is a city in Gujarat, India, known for its chemical and pharmaceutical industries. The city is home to over 100 chemical and pharmaceutical companies. The chemicals and pharmaceuticals manufactured in Vapi are exported to over 100 countries around the world.