Table 3 represents production data for a competitive firm Number of workers Output 0 0 5 11 19 25 29 31 31 8 30 Table 3 Refer to Table 3, the law of diminishing returns sets in with the addition of the _worker. Select one: Oa / O b. 2 OC. 4 Od. 1 here to searchAll of the following statements about variable costs are true EXCEPT Select one: O a. they are constant as output increases O b. they are zero if output is zero. O c. they are equal to the product of average variable cost and the output level. O d. they are equal to total costs in the long run