A souvenir shop sells special mugs at a price of $15 each and at that price, a total of 450 mugs are sold per month. The store manager estimates that for every $1 increase in the price of the mug. 18 fewer mugs will be sold per month. If the price of the mug increases by x dollars, which of the following functions best models the estimated monthly revenue R(x), in dollars, generated from selling the mugs? The revenue generated from
selling the mugs can be found by multiplying the price of the mug by the number of mugs sold)