I need help with c) & d) of attached problem. Thank you!

3) Two firms produce a homogeneous product and compete in prices. Inverse demand is P(Q) = D - Q. Firm 1 has a constant marginal cost of c1 and firm 2 has a constant marginal cost of C2. Assume that D > C2 > C1 > 0. a) Solve for the competitive equilibrium price and output level for each firm. b) Solve for the Cournot equilibrium price and output level for each firm. c) What is the total deadweight loss arising from Cournot competition in this market? d) Productive inefficiency refers to the extra costs to produce a given amount relative to the lowest cost method of producing that amount. How much of this loss is due to productive inefficiency rather than market power