[Grammar] It tries to interpret and to evaluate such works and to examine the principles ___ th

[tahasozgen]

Critism is the analysis and judgement of works of art. It tries to interpret and to evaluate such works and to examine the principles ___ they may be understood.


A) of whose
B) where
C) that
D) by which
E) whom


My answer is B. Key depicts D. Why? Thanks in advance.

 

[jutfrank]

You understand something by a certain principle.