The correct answer is: a) Surat.
Surat is a city in the Indian state of Gujarat. It is the second-largest city in Gujarat, after Ahmedabad, and the 10th-largest city in India. Surat is known for its diamond polishing industry, and is also a major manufacturing hub for textiles, chemicals, and engineering goods.
Rajkot is the second-largest city in Gujarat, after Ahmedabad. It is the administrative headquarters of Rajkot district and Saurashtra region. Rajkot is a major commercial and industrial center, and is also home to a number of educational institutions.
Bhavnagar is a city in the Indian state of Gujarat. It is the third-largest city in Gujarat, after Ahmedabad and Surat. Bhavnagar is a major port city, and is also home to a number of industries, including textiles, chemicals, and engineering goods.
Gandhinagar is the capital of the Indian state of Gujarat. It is a planned city, and was founded in 1960. Gandhinagar is home to a number of government offices and institutions, and is also a major educational center.