The correct answer is: Both A and R are true but R is not a correct explanation of A.
Abul Fazl, Akbar’s official historian, does not give the prices of slaves nor does he mention slave markets. This does not necessarily mean that Akbar prohibited slave trade in his empire. It is possible that Abul Fazl did not consider it important to mention the prices of slaves or slave markets, or that he did not have access to this information. It is also possible that Akbar did prohibit slave trade, but that Abul Fazl did not mention it because he did not think it was a significant event.
In conclusion, both A and R are true, but R is not a correct explanation of A.