18) The total revenue for the sale of x items is given by: R(x) = -190√x 3+x3/2 Find the marginal revenue R'(x). A) R'(x)= 95(3x-1/2-2x) 3+x3/2 C) R'(x) = 95(3x-1/2-2x) (3+x3/2)2 B) R'(x) = 95(3x1/2