At a certain store, the taco sauce was on sale for 1/5 off. with a coupon for an additional 40 cents off, the final cost of the sauce was $1.20.

which equation will marvin to figure out how much his payment will be?
let x = one installment

a) c - 1/5c + 40 = 120
b) c - 1/5c - 40 = 120
c) 1/5c = 120 - 40
d) 1/5c = 120 + 40