The following table shows the cost of a shirt for each week during a sale. what is the rate of change for this situation?
week price
1 $32.50
2 $30.00
3 $27.50
4 $25.00

a) $7.50 per week

b) -$7.50 per week

c) -$2.50 per week

d) $2.50 per week