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

Multiple Choice

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

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