Problem: Two small business owners rent store fronts next to each other and share a parking lot. In winter, the owner of the dog grooming business pays to have the entire parking lot cleared of snow. In exchange, each spring the owner of the screen-printing business makes new staff shirts for the dog groomer's employees. Neither business claims this exchange on their taxes. Which statement is true of this situation? (a) Neither owner is doing anything illegal, the costs even out. (b) The screen-printer is in the wrong by not claiming the "free" snow removal on their taxes. (c) The dog groomer is in the wrong by not claiming the "free" staff shirts on their taxes. (d) Both owners are doing something illegal by not claiming the value of either snow removal or staff shirts on their taxes.