The Tang helped promote buddhism throughout China by a. Officially banning all other belief systems
b. Mandated the Buddhist themes be included on all Civil Service Exams
Provided tax breaks for lands with Buddhist temples
d. Adopting the Buddhist Calendar as the official Chinese calendar
C.

Option A

Explanation:

In early days of China, the belief of Confucianism was prevailing that later disillusioned (disappointed) people and was unable to keep order in China and following this the empire of China broke into smaller pieces. People got embraced with Buddhism, a new religion as it believes on "end to suffering"

Later on, Buddhism was officially made the one and only belief system of China.

Hence, option A is correct

you so !