Why might The Pillow Book be seen as a less-than-credible source?

I believe it is B.

Explanation:

It cannot be A, because diaries can be used as primary sources if the person that is writing experienced what had happened.

It cannot be C, because primary sources can have opinions.

And it cannot be D, because the question is looking for why it is a less-than-credible source.

I hope this helped. Good luck with your Edge Test!!! :D

answer; i believe that the correct answer is ; the eastern and western churches spoke different languages;