The graph of a linear function h contains the points given in the table below.

Find h^-1. x y
-2,4
-1,2
1,-2
2,-4

a.h^-1(x)=2x
b.h^-1(x)=-2x
c.h^-1(x)=1/2x
d.h^-1(x)=-1/2x