Which situations can be represented by an exponential function? Select each correct answer. A. Every year, the number of online subscribers to a service is 4 times what it was the previous year.

B. The value of a motorcycle decreases by 12% year year.

C. In a structure made of soup cans, each row has 6 more cans than the previous row.

D. A doctors office accepts 20 new patients each month.