Number of Goldfish Cost 5 $1.50 10 $3.00 15 $4.50 20 $6.00 The cost is a linear function of the number of goldfish. Which statement describes the rate of change of this function? A. The cost increases $0.30 each time 1 goldfish is added. B. The cost increases $1.50 each time 1 goldfish is added. C.The cost increases $3.00 each time 5 goldfish are added. D. The cost increases $6.00 each time 5 goldfish β