Answer: C. He was too busy working at a job he hated to enjoy his life.
The Metamorphosis by Franz Kafka tells the story of a clerk who one day wakes up and notices he has turned into a giant insect.
Althought the story begins at this point, there is some information that can be inferred about the character's past. We find out that through his work, he supports his whole family. This sense of responsibility makes him unable to quit, even though he hates it and it does not allow him to enjoy his life as he would like to.