Hibbert plc has calculated their gross profit % to be 45% in 2014 compared to 37% in 2013. Which of the following! statements is unlikely to be an explanation for the improved results? Select one: a. A cheaper supplier of raw material was found O b. Change to the minimum wage increased the production labour rate per hour C. Competitor withdrawal from the market place enabled the company to increase their selling prices d. Improved machine efficiency