Answer:
B. Gregor wakes up in his bed to discover that he has been turned
into a giant, hideous bug.
Explanation:
Rising action takes place after the introduction of the characters, setting etc. It is usually an event or a series of events in a plot that create the condition for conflicts to arise and to be solved. That is, if it weren't for the rising action, there would be no suspense, no problem, no climax or resolution. In "The Metamorphosis", the rising action begins when Gregor wakes up transformed into a bug. Technically speaking, everything that happens from then on could be thought of as part of the rising action. But, if we want to me more precise, the events provided in options A and C could be considered conflicts, while the event on letter D is the resolution for the conflict. Thus, the event in the rising action cause a conflict and its resolution:
Gregor is now a bug --> his family is disgusted and not sure if they should accept him --> Gregor dies, and his family is now relieved of the burden
