On a Diagram Wherein the Interest Rate and the Quantity

On a diagram wherein the interest rate and the quantity of money demanded are shown on the vertical and horizontal axes respectively, the total demand for money can be found by:

A) horizontally adding the transactions and the asset demand for money.
B) vertically subtracting the transactions demand from the asset demand for money.
C) horizontally subtracting the asset demand from the transactions demand for money.
D) vertically adding the transactions and the asset demand for money.