The answer is A: Kafka's lifelong feelings of inadequacy.
Although reading Kafka´s private correspondence and his diaries show a picture of a troubled man, though one provided with an acute and brilliant sense of humor and irony that he knew made him exceptional, one also gets the image of a man who feels, at times, unable to perform the most basic social duties or the simplest of personal tasks. In Metamorphosis, the latter sense of inadequacy is most clearly felt, not without leaving in the reader a sense of dread and horror at the depth of Samsa´s (the main character in the story) doubts.
