$59-64$ Match the function $($a$)$ with its graph $($labeled A$-$F below$)$ and $($b$)$ with its contour map $($labeled I$-$VI$).$ Give reasons for your choices.

$59.z=sin(xy)$

$60.z=e^{x}cosy$

$61.z=sin(x-y)$

$62.z=sinx-siny$

$63.z=(1-x^2)(1-y^2)$

$64.z=\frac{x-y}{1+x^2+y^2}$

B

C

E

F

$1$

Iv

VI