Mia opens a coffee shop in the first week of january. the function w(x) = 0.002x3 - 0.01x2 models the total number of customers visiting the shop since it opened after x days. she then opens an ice cream parlor in the month of february. the function r(x) = x2 - 4x + 13 models the total number of customers visiting the parlor since it opened after x days. which function represents the difference, d(x), in the number of customers visiting the two shops? a. d(x) = 0.002x3 + 1.01x2 - 4x + 13 b. d(x) = 0.002x3 + 0.99x2 + 4x - 13 c. d(x) = 0.002x3 - 1.01x2 + 4x - 13 d. d(x) = 0.002x3 - 0.99x2 - 4x + 13