The table below shows the cost of different numbers of goldfish at a pet store.

5$1.50

10---$3

15---$4.50

20---$6

Which statement describes the rate of change of this function?

A.

The cost increases $3.00 each time 5 goldfish are added.

B.

The cost increases $0.30 each time 1 goldfish is added.

C.

The cost increases $6.00 each time 5 goldfish are added.

D.

The cost increases $1.50 each time 1 goldfish is added.