Suppose that the production function for DVDs is given by Q = KLZ L3, where Q is the number of disks produced per year, Kis machine-hours of capital, and L is man-hours of labor. Suppose K = 600. When L = 0, Q=_. At L =_, the total product is the highest. At L = , the average product of labor is the highest. At L = _. the marginal product of labor is the highest. At L = 400, the marginal product of labor is _