Question $13$

$2$ pts

The rule for making an investment is to do so as long as:

the marginal product of capital is greater than or equal to the world real interest rate $($DQ$/$DK $($:${?}^3{r}^{**}\}.$

the initial level of wealth is equal to zero.

the marginal product of labor is positive $(D\frac{Q}{D}L>0).$

the marginal product of capital is positive $($DQ$/$DK$>0).$