Which phone plan has the better deal and why?

phone plan A = retail price : $500 cupon : 25% off sale price : x

phone plan B = retail price : $435 cupon : 50% off sale price : x

Complete the table above to calculate the better deal.

a . Plan A is a better deal because it is $40 less than Plan B

b. Plan A is a better deal because it is $10 less than Plan B

c. Plan B is a better deal because it is $10 less than Plan A