Which answer describes the calculations that could be used to solve this problem?

juan bought 8 tickets for the movie theater. each ticket cost $9. he gave the cashier $80. how much change would juan get?

a.
multiply 8 × $9. then subtract the product from $80.

b.
divide $80 ÷ 8. then add $9 to the quotient.

c.
add $9 + 8. then subtract the sum from $80.

d.
multiply $80 × 9. then add $8 to the product.