The correct answer is: c) Prehistoric indigenous practices.
Sikkim is a state in northeastern India. It is located in the Himalayas and is bordered by Bhutan, China, Nepal, and West Bengal. The majority of the population of Sikkim is Buddhist, but there are also significant Hindu and Christian minorities.
Pre-Buddhist animistic beliefs and nature worship are still prevalent among some communities in Sikkim. These traditions likely have roots in prehistoric indigenous practices.
Prehistoric indigenous practices are the beliefs and practices of the people who lived in Sikkim before the arrival of Buddhism. These practices are often based on the belief that all living things are interconnected and that nature is sacred.
The influence of the Namgyal Dynasty is not likely the source of these traditions. The Namgyal Dynasty was a Tibetan Buddhist dynasty that ruled Sikkim from the 17th century to the 1970s. While they did influence the culture of Sikkim, they did not introduce animistic beliefs and nature worship.
Early Hinduism is also not likely the source of these traditions. Hinduism is a religion that originated in India. It is a polytheistic religion that believes in many gods and goddesses. While Hinduism is the majority religion in India, it is not the majority religion in Sikkim.
Arrivals from Southeast Asia is also not likely the source of these traditions. Southeast Asia is a region of Asia that is located south of China and east of India. It is home to many different cultures and religions. While there have been some cultural exchanges between Southeast Asia and Sikkim, it is unlikely that animistic beliefs and nature worship originated in Southeast Asia.
In conclusion, the correct answer is: c) Prehistoric indigenous practices.