National Highway 10 (NH10) is a key road link connecting Sikkim to West Bengal. It is a two-lane highway that runs from Sevoke in West Bengal to Gangtok in Sikkim. The highway is 120 kilometers long and is a major tourist attraction. It offers stunning views of the Himalayas and the Teesta River. The highway is also an important trade route between India and China.
Option a: West Bengal is the correct answer. NH10 connects Sikkim to West Bengal.
Option b: Nepal is not connected to Sikkim by NH10. The two countries are separated by the Indian state of West Bengal.
Option c: Bhutan is not connected to Sikkim by NH10. The two countries are separated by the Indian state of West Bengal.
Option d: China (Tibet) is not connected to Sikkim by NH10. The two countries are separated by the Indian state of Sikkim.