Answer:
C-$24
Step-by-step explanation:
At optimal combination of inputs that is at the equilibrium level the ratio of marginal productivity of labor to the marginal productivity of capital is equal to the ratio of price of labor(wage) to the price of capital(rent). That is ,
MPL/MPK = W/R
WHERE , MPL = MARGINAL PRODUCTIVITY OF LABOR
MPK = MARGINAL PRODUCTIVITY OF CAPITAL
W = WAGE
R = RENT
SO , AS GIVEN , 15/45 = 8/R
SO , R = 8*3 = $24.
SO ANSWER IS OPTION C.$24