Which of the following is not a determinant of Investment spending?

The conditions for a valid instruments do not include the following:

A) each instrument must be uncorrelated with the error term. B) each one of the instrumental variables must be normally distributed. C) at least one of the instruments must enter the population regression of X on the Zs and the Ws. D) perfect multicollinearity between the predicted endogenous variables and the exogenous variables must be ruled out.

A worker can always build a chair in four hours. If a chair sells for $40 in a perfectly competitive market, then the equilibrium wage per hour in a perfectly competitive labor market is

a. $4. b. $10. c. $40. d. $160.