planned real investment is determined by the\na. money supply.\nb. the marginal tax rate.\nc. rate of…

Brief Explanations:

The rate of interest is a crucial factor in determining planned real - investment. When the interest rate is low, borrowing money for investment is cheaper, so firms are more likely to invest. Higher interest rates increase the cost of borrowing, reducing the incentive for firms to invest. The money supply affects overall economic conditions but not directly determine planned real investment in a straightforward way as the interest rate does. The marginal tax rate affects after - tax profits but not as directly as the interest rate on investment decisions. The marginal propensity to save is related to consumption and saving behavior, not directly to investment decisions.

Answer:

C. rate of interest