The predominant religion in Sikkim is:

Hinduism
Buddhism
Christianity
Islam

The correct answer is: b) Buddhism.

Sikkim is a state in northeastern India. It is bordered by Bhutan to the north, China to the east, Nepal to the west, and West Bengal to the south. The capital of Sikkim is Gangtok.

The predominant religion in Sikkim is Buddhism. According to the 2011 census, 81.5% of the population of Sikkim is Buddhist. The majority of Buddhists in Sikkim are Vajrayana Buddhists.

Hinduism is the second largest religion in Sikkim, with 12.9% of the population following the religion. The majority of Hindus in Sikkim are Shakta Hindus.

Christianity is the third largest religion in Sikkim, with 5.8% of the population following the religion. The majority of Christians in Sikkim are Roman Catholics.

Islam is the fourth largest religion in Sikkim, with 0.6% of the population following the religion. The majority of Muslims in Sikkim are Sunni Muslims.

Other religions, such as Jainism, Sikhism, and animism, are also practiced in Sikkim.