The demand for a certain portable USB battery charger is given by D(p) = - 3p- + 3p + 2, where p represents the price in dollars. (a) Find the rate of change of demand with respect to price. (b) Find and interpret the rate of change of demand when the price is $13 (a) The rate of change of demand with respect to price is (b) Select the correct choice below and fill in the answer box to complete your choice A. Demand is decreasing at a rate of 1 item per S decrease in price B. Demand is increasing at a rate of 1 item per $ increase in price Demand is decreasing at a rate of items per $1 increase in price D. Demand is increasing at a rate of items per $1 increase in price