Find the Jacobian of the Transformation $x = r \cos \theta$

Multiple Choice

Find the Jacobian of the transformation $x = r \cos \theta$ , $y = r \sin \theta$ , z = z.

A) $\theta$
B) z
C) r
D) 1
E) 2 $\theta$
F) 2z
G) 2r
H) 2