The Teesta River is a major water source for:

East Sikkim and South Sikkim
North Sikkim and West Sikkim
East Sikkim and North Sikkim
All districts of Sikkim

The correct answer is: d) All districts of Sikkim.

The Teesta River is the main river in Sikkim, India. It originates in the Himalayas and flows through the state before joining the Brahmaputra River in West Bengal. The Teesta River is a major source of water for irrigation, drinking water, and hydroelectric power in Sikkim. It is also a popular tourist destination, with many people visiting the river to go swimming, fishing, and boating.

The Teesta River is a major water source for all districts of Sikkim. It is the main source of irrigation water for the state’s agricultural sector. The river is also a major source of drinking water for the people of Sikkim. The Teesta River is also a major source of hydroelectric power for the state.

The Teesta River is a vital part of the economy and environment of Sikkim. It is a major source of water for irrigation, drinking water, and hydroelectric power. The river is also a popular tourist destination. The Teesta River is a beautiful and important river that is essential to the well-being of Sikkim.

The other options are incorrect because they do not include all districts of Sikkim. Option a) includes only East Sikkim and South Sikkim. Option b) includes only North Sikkim and West Sikkim. Option c) includes only East Sikkim and North Sikkim.