"Silvi has a coupon for $5 off any one item at her favorite store. She mt pay 6% sales tax on the discounted price. Which of the following functions represents Silvi's final cost, c, for an item with an original price of x dollars? a. c(x) = 0.94x - 5 b. c(x) = 0.94(x - 5) c. c(x) = 1.06x - 5 d. c(x) = 1.06(-5)