Answer:
D) vertical line
Explanation:
The liquidity preference simply means the demand for money, since money (cash) is the most liquid asset. The demand for money varies depending on the price for money, or the interest rate. The Fed determines the money supply by changing the interest rate, e.g. when the interest rate deceases, the Fed purchases securities and increases the money supply. The money supply curve is always vertical, since the Fed determines it by changing the interest rate.