Which one of the following is not a sect of Buddhism?

The correct answer is C. Digambar.

Mahayana and Theravada are the two main sects of Buddhism. Mahayana is the larger of the two, and it is practiced in East Asia, Central Asia, and North America. Theravada is practiced in Southeast Asia.

Digambar is a sect of Jainism, not Buddhism. Jainism is an ancient Indian religion that emphasizes non-violence and asceticism.