Rachel has missed several classes because of family issues. On the day of the midterm, Rachel asks ...

Rachel has missed several classes because of family issues. On the day of the midterm, Rachel asks you, her classmate, if she can copy your answers so that she does not fail the exam. According to Kohlberg, how would you respond if you were using postconventional moral reasoning?
 
  a. No way I could get caught by the instructor, and then I'd fail.
  b. I cannot let you cheat because it would be unfair to the other students.
  c. Okay. As a friend, it's my duty to help you.
  d. I'll let you copy my answers, but you owe me a favor now.