Which of the following is an example of a complementary service?

Select one:

A$.$

Chesterton College hires part$-$time teachers when enrollment goes up$.$

B$.$

AXA Bank set up automated teller machines so that its customers could avoid standing in line.

C$.$

More paramedics are on hand to assist physicians during times when emergency admissions are highest.

D$.$

The Caesar Park Hotel generally caters to business customers during the week, but has now decided to promote mini$-$vacation weekends for non$-$business customers as well.

E$.$

Big department stores usually hire extra staff to handle the rush during the holiday season.