In the above table, between what two levels of output does one first observe the law of diminishing returns? Labor (workers) Total product (units) 0 0
5 1000
10 3000
15 4000
20 4500 Select one: a. 4000 and 4500 b 1000 and 3000 c 0 and 1000 d. 3000 and 4000