Mike became a father. He felt a strong sense of responsibility towards his parents.

A. Were Mike to become a father himself, he would feel a strong sense of responsibility towards his parents.

B. Only after Mike had become a father himself did he feel a strong sense of responsibility towards his parents.

C. Had Mike become a father himself, he would have felt a strong sense of responsibility towards his parents.

D. Not until he felt a strong sense of responsibility towards his parents did Mike become a father himself.