Selling a Good at a Price Determined by the Intersection

Selling a good at a price determined by the intersection of the demand curve and the marginal cost curve is consistent with the
(i) socially-optimal level of output.
(ii) market solution for profit-maximizing competitive firms.
(iii) market solution for a profit-maximizing monopoly.

A) (i) and (ii) only
B) (ii) and (iii) only
C) (i) and (iii) only
D) (i) , (ii) , and (iii)