If an aggregate demand curve is drawn with real GDP (Y) along the horizontal axis and the price level (P) along the vertical axis, using the quantity theory of money as a theory of aggregate demand, this curve slopes ______ to the right and gets ______ as it moves farther to the right.
选项：

A:downward; steeper
B:downward; flatter
C:upward; steeper
D:upward; flatter