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.
A passive voice is whenever you make the object of an action the subject of the sentence you are writing. (Ex: Why was the road crossed by the chicken?)
An active voice is whenever you make the subject of the sentence doing the verb's action. (Ex: The chicken crossed the road.)
