The Marginal Benefit of Reducing Pollution and the Marginal Cost

The marginal benefit of reducing pollution and the marginal cost of reducing pollution are given by the following equations: MB = -2U² + 18,and MC = 2U² + 2,where U is the number of units of pollution abatement.What is the net marginal benefit (MB - MC) of abating the first unit of pollution (U = 1) ?

A) 10
B) 12
C) 14
D) 16
E) 18