A: You can't say it's A. We don't know that he was a former employee.
B: We don't know anything about his shopping experience.
C: He's not proud. He doesn't think Shop-Mart is a good thing.
D: I'm not sure that bitter is the right word. Sad may be better and I'm not sure about which community he is dissatisfied seeing harmed. Nevertheless, D is best answer, because that's what Shop Mart did.
