The choices for this question can be found elsewhere and as follows:
a. expanded to become the dominant religion in all of Asia. . .
b. declined in India but remained strong in other areas of Asia. . .
c. spread to Asia but did not take hold throughout the continent. . .
d. became obsolete when Hinduism spread into Asia.
The correct answer from the choices would be option option B. Buddhism was India’s dominant religion in 100 BCE, and then it declined in India but remained strong in other areas of Asia.