Your favorite dog groomer charges according to your dog's weight. If your dog is 15 pounds and under, the groomer charges a flat fee of $35. If your dog is between 15 pounds and up to 40 pounds, then she charges a flat fee of $40. If your dog is over 40 pounds, then she charges $40 plus an additional $2 for every pound the dog is over 40 pounds. Let represent the weight of the dog. Which of the following piecewise functions represents the above problem?