Suppose the demand for a certain ilem is given by D[p]=-3p2-6p400, where p represerts the price of the ham in dollars.a. Find the rate of change of demand with reseect to prioe.b. Find and interpret the rate of change of demand when the grice is $13.a. The rate of charge of demand with retepect to price is D'(p)"(Simplify your answer)b. Choose the correct anower below and fill in any answer bous in your choile.A. When the prise is $13, demand is increasing at a rais at aboutHems for each increase in price of $13.B. When the prise is $43, demand is decreasing at a rate of aboutRems for eath increase in pelice of $13.C. When the price is $13, demand is increasing at a rais al aboutlems for each increase in price of $1.D. When the prise is $13, demand is decreasing at a rate of abouthemsfor each increase in price of $1.