Answer:
C. splendor
Step-by-step explanation:
Let's first take a look at the word resplendent.
Resplendent is made up of the Latin roots re, and splendere.
A, interrogate, has none of these roots. Same goes for B.
C, splendor, however, includes the root splendere. Thus, this is the correct answer.
Hope this helps!
Note: the Latin root splendere means "to glitter".