The correct answer is option C - Nepal.
Buddhism is an Indian religion. It is a path of practice and spiritual development that leads insight the true nature of life. People who practice Buddhism, called Buddhists, seek to reach a state of Nirvana, which is a state of perfect peace and happiness
Nowadays, there are 376 million followers all over the world. Buddhism is widely practiced in Nepal which was the country of Budha's birth. Besides, Nepal is the only Buddhist society that keeps casts distinctions between the monasteries.