An upstart phone company has only two potential large customers, Firm A and Firm B. Firm As monthly demand for phone calls is Q1 = 2; 800 - 200p and Firm 2s is Q2 = 5; 000 - 100p. The marginal cost of providing a phone call is 6 cents. Assuming the phone company has to charge the same monthly rental fee and unit price to all its customers, at what level should it set these charges?