The Equilibrium Quantity of Capital Is

The equilibrium quantity of capital is

A) determined by only the supply of capital because the supply is perfectly inelastic.
B) determined by only the supply of capital because the supply is perfectly elastic.
C) expected to increase at the same rate as the interest rate.
D) determined by the supply of capital and the demand for capital.
E) the only factor of production whose quantity is not determined in a market.