Which of the following is an example of how a service firm might turn unused capacity into revenue using incremental analysis?

a) An instructor agrees to add an additional student to a class.

b) A manufacturing firm that rents assembly line space to a complementary company.

c) An accountant with no extra time agrees to do an extra client's tax return during busy season.

d) A train company uses a last-minute app to fill empty seats and makes long-term pricing decisions based on average revenue.