Find the Jacobian of the Transformation $$x = 5 \alpha \sin \beta , y = 4 \alpha \cos \beta$$

Multiple Choice

Find the Jacobian of the transformation.
$$x = 5 \alpha \sin \beta , y = 4 \alpha \cos \beta$$

A)
$\frac { \partial ( x , y ) } { \partial ( \alpha , \beta ) } = 9 \alpha$
B)
$\frac { \partial ( x , y ) } { \partial ( \alpha , \beta ) } = 36 \alpha$
C)
$\frac { \partial ( x , y ) } { \partial ( \alpha , \beta ) } = - 20 \alpha$
D)
$\frac { \partial ( x , y ) } { \partial ( \alpha , \beta ) } = - 20 \alpha \sin \beta \cos \beta$
E)
$\frac { \partial ( x , y ) } { \partial ( \alpha , \beta ) } = - \alpha$