The religion that spread from India and China throughout much of Southeast Asia is Buddhism. To arrive at this answer, one can analyze the options provided: Hinduism, Islam, Confucianism, and Buddhism. From here, one can eliminate the options based on their geographical origins and historical spread. Hinduism originated in India and while it has influenced Southeast Asian cultures, it did not spread as extensively as Buddhism. Islam originated in the Arabian Peninsula and gradually spread to Southeast Asia through trade routes and missionary activities. Confucianism, on the other hand, originated in China and primarily influenced East Asian societies. Only Buddhism, which originated in India and then spread to China, Southeast Asia, and other parts of Asia, matches the criteria of a religion spreading from India and China throughout much of Southeast Asia. Therefore, the correct answer is A. Buddhism.
