Which of these factors contributed to Buddhism's popularity?

Buddhism's popularity can be largely attributed to its rejection of the caste system, a rigid social hierarchy prevalent in ancient India. By advocating for the idea that anyone, regardless of their social status, could attain enlightenment and nirvana, Buddhism appealed to those who were marginalized by the strict social divisions of the time. This inclusivity allowed it to attract a diverse group of followers, including those from lower castes who found the Brahmanical religion inaccessible and exclusive.

The rejection of the caste system suggested a path to spiritual fulfillment that was open to all, which was particularly appealing during a period when many were seeking alternatives to the traditional religious practices that were often intertwined with caste distinctions. This characteristic made Buddhism not only a religious choice but also a social movement that resonated with the socio-political context of its time, facilitating its wider acceptance and growth.