For the demand function q = D(p) = 219-p, find the following. a) Find the equation for elasticity. b) Find the elasticity at the given price, stating whether the demand is elastic, inelastic or has unit elasticity. Is the demand elastic, inelastic, or does it have unit elasticity? c) Find the value(s) of p for which total revenue is a maximum (assume that p is in dollars). $ (Round to the nearest cent. Use a comma to separate answers as needed.)