The price p (in dollars) and the demand x for a particular clock radio are related by the equation x = 4000 - 20p. (A) Express the price p in terms of the demand x, and find the domain of this function. (B) Find the revenue R(x) from the sale of x clock radios. What is the domain of R? (C) Find the marginal revenue at a production level of 2400 clock radios. (D) Interpret R'(3100) = - 110.00. (A) p = p(x)=