The shortest term security sold by the US is the:

If technological change is "neutral," then

A) output per worker declines, output per unit of capital increases. B) "effective labor input" increases, output per unit of capital declines. C) output per worker increases, output per unit of capital is constant. D) Both output per worker and output per unit of capital change.

At the profit-maximizing level of output, marginal profit

A) is also maximized. B) is zero. C) is positive. D) is increasing. E) may be positive, negative or zero.