The Marginal Cost of a Monopolist Is Constant and Is

The marginal cost of a monopolist is constant and is $10. The demand curve and marginal revenue curves are given as follows: demand: Q = 100 - P
Marginal revenue: MR = 100 - 2Q
The deadweight loss from monopoly power is:

A) $1000.00.
B) $1012.50.
C) $1025.00.
D) $1037.50.
E) none of the above