What Historical Problem Is Involved in Ashoka's Claim That He

What historical problem is involved in Ashoka's claim that he spread Buddhism beyond the borders of northern India by supporting dharma?

A) While he did send missionaries, there is no independent evidence of Buddhism spreading outside India during Ashoka's reign.
B) Most documents of Ashoka's reign were destroyed after his death.
C) The only mention of this phase in Ashoka's reign comes from later Buddhist sources.
D) Any records showing that Ashoka had violated his vows to the Buddha would have been destroyed.
E) Records of this phase of Ashoka's reign might have merely been used as propaganda to enhance his image.