How did the fall of the han dynasty encourage the introduction of new, non-chinese religions into china?
a. with the revocation of the mandate of heaven, there was no institution to stop the spread of alien religions
b. the last han emperor had been interested in religions of salvation and so introduced the ideas to the bureaucrats and it filtered down to chinese citizens
c. the confucian tradition lost credibility after the fall of the han, and the era of warlords and nomadic invaders promoted the spread of foreign religions into china
d. the han dynasty had actively sought to eradicate buddhist monasteries from china, and with its demise the buddhists saw an open door into china's elite society