Pharmaceutical manufacturing is emerging as a potential growth area in Sikkim, with the establishment of units in:

The correct answer is: b) Gangtok.

Gangtok is the capital of Sikkim and is the largest city in the state. It is located in the eastern Himalayas and is a popular tourist destination. The city is home to a number of pharmaceutical companies, including Sun Pharmaceutical Industries, Lupin Limited, and Cadila Healthcare. These companies have established manufacturing units in Gangtok in order to take advantage of the state’s low labor costs and favorable investment climate.

The other options are incorrect because they are not cities in Sikkim. Namchi is a town in South Sikkim district, Jorethang is a town in West Sikkim district, and Gyalshing is a town in East Sikkim district.