Which of the following points constitute the marginal productivity theory? Check all that apply. Marginal factor cost is diminishing and is lower than its factor price. Firms hire the factor quantity at which marginal revenue product is lower than marginal factor cost. Firms hire the factor quantity at which marginal revenue product equals marginal factor cost. Marginal factor cost of a firm that is a factor price taker, is constant and equal to its factor price. Suppose that Paolo works for Clear Drop Co, a perfectly competitive firm producing water filters. Paolo was paid $5,000 but found a better job and quit Clear Drop. Since nothing else changed, Clear Drop's total revenuefalls by $5,000