Your friend Sharon says that if she skips classes today she could go to work for five hours where she earns $15 an hour. When at the college she usually parks in the campus parking lot with her annual parking permit which costs her an equivalent of $3 per day. From this, you can deduce that Sharon's opportunity cost of attending class today is

Select one:

a. $72

b. $78

c. $3

d. $75