Gregor was quite confused of how he changed in the dream therefore he was heavily affected by it and soon came to past. He felt sad when the raindrops pittered and pattered on the window pane which indeed matched his mood of how he was. But when his mother asked him if he wanted to go somewhere he replied in a forced but uncertain tone. Henceforth he felt partially full because of the meaning of how it had happened.
The second answer is the closest.
Im 85% sure that the answer c
A theme could be "life or death" because throughout the novel because for an example Montags wife attempts suicide until montag finds her and calls for emergency help and saves her life, and while they were trying to help her its unclear if she was going to live or die, so while all this is happening monag starts to womder what life really is.