The correct answers are: B) the dystopian world that Gregor enters as an insect, and C) Gregor's sudden transformation into a giant insect.
A Kafkaesque situation is a nightmarish one, and also strongly surreal, so in that sense, the options that relate the most to said expression are the ones that have to do with dream-like things, like the dystopian world and Gregor becoming an insect.
The answer is C.
Hope this helps!
Thinking about Grendel, I think 'A' is most likely.
