Answer: The correct answer is 150 UNITS.
Explanation: The table is :
Labor / Output / Marginal Product / Variable Cost / Fixed Cost
0 0 -- $0 $5
1 100 100 $5
2 250 $10
3 350 $15
4 50 $20
5 25 $25
6 430 $30
And the Marginal product is it is the variation that the production of a good experiences when increasing a unit of a productive factor of the same, remaining the rest constant.
Therefore 250 - 100 = 150.