A local pizza place has a special deal on Thursday: Buy a large one topping pizza for $12 and each order of cheesy bread is $2.50. This creates a linear equation that represents the cost of the purchase of multiple orders of cheesy bread. What would be the rate of change in this word problem?
 ]A. 2.5
 B. 1/ 2.5
 C. 4.8
 D. 1/4.8