When a Tax Is Imposed on a Good,at the After-Tax

When a tax is imposed on a good,at the after-tax equilibrium the marginal benefit of the last unit produced ________ the marginal cost.

A) equals
B) is greater than
C) is less than
D) can be calculated but is not comparable to
E) The premise of the question is incorrect because after a tax is imposed, it becomes impossible to determine the marginal benefit and the marginal cost.