If a firm must lower its price to sell more of a good, which of the following must also be true? Choose 1 answer: Choose 1 answer: (Choice A) Its marginal revenue curve is upward-sloping. A Its marginal revenue curve is upward-sloping. (Choice B) Its marginal revenue curve is equal to its demand curve. B Its marginal revenue curve is equal to its demand curve. (Choice C) Its marginal revenue curve is the same as its marginal cost curve. C Its marginal revenue curve is the same as its marginal cost curve. (Choice D) Its marginal revenue curve is lower than its demand curve. D Its marginal revenue curve is lower than its demand curve. (Choice E) Its marginal revenue curve is higher than its average total cost curve. E Its marginal revenue curve is higher than its average total cost curve