Sunshine's organic market sells organic produce. assume that labor is the only input that varies for the firm. the store manager has determined that if she hires 9 workers, the store can sell 200 pounds of produce per day. if she hires 10 workers, the store can sell 230 pounds of produce per day. the store earns $4 for each pound of produce that it sells, and the manager pays each worker $60 per day. which of the following is correct? select one: a. all of the above are correct. b. the marginal profit from the 10th worker is $120.c. for the 10th worker, the marginal product is 20 pounds of produce per day. d. for the 10th worker, the marginal revenue product is $120 per day.