To find the marginal product of the second laborer, we need to look at the change in total product when we increase the quantity of the second laborer by one unit while holding capital constant at 3 units.
From the table, we can see that when L = 1 and K = 3, the total product is 2. When L = 0 and K = 3, the total product is 0. Therefore, the change in total product when we increase L from 0 to 1 while holding K constant at 3 is 2 - 0 = 2.
Thus, the marginal product of the second laborer is 2.
Therefore, the correct answer is:
A. 8.