The missing pages in dr. yu tsun's statement become an extended metaphor
that alludes to missing text in other ancient literary works
that solve the mystery
when they unravel the fate of ts'ui pên
because ts'ui pên had also been missing

Explanation:

The pretentious student of history continues to reveal his trump card. It's a statement or a type of oral declaration given by an observer to be utilized in a preliminary. For this situation, the affidavit is managed by a man named Dr. Yu Tsun, and the initial two pages are absent.  

The remainder of the story is the testimony, told from the perspective of Dr. Yu Tsun. Since the initial two pages are "missing," we begin in mid-sentence.

keep learning.

explanation:

i guess

i think that it is letter d.