The correct answer is: a) South Sikkim
South Sikkim is the district with the highest forest cover in Sikkim. It has a forest cover of 76.6%, which is the highest among all the districts in Sikkim. The main reason for this is that South Sikkim is home to the Khangchendzonga National Park, which is the largest national park in Sikkim and one of the largest national parks in India. The park is home to a variety of plant and animal life, including many endangered species.
The other districts in Sikkim also have a high forest cover, but not as high as South Sikkim. North Sikkim has a forest cover of 72.5%, West Sikkim has a forest cover of 69.2%, and East Sikkim has a forest cover of 67.8%.
The high forest cover in Sikkim is important for a number of reasons. It helps to protect the environment, it provides habitat for wildlife, and it helps to regulate the climate. The forest cover in Sikkim is also important for the local economy. The forest provides a source of income for many people in Sikkim, and it is also a popular tourist destination.