Let $f ( x , y ) = x + 2 y$

Multiple Choice

Let $f ( x , y ) = x + 2 y$ . Then $f ( x + \Delta x , y ) - f ( x , y )$ is

A) $\Delta x + 2 y$
B) $\Delta x$
C) $\Delta x + 2 \Delta y$
D) $\Delta x - 2 y$
E) $\Delta x - 2 \Delta y$