5. Match the functions below up with both a graph and a contour map, and explain why they match up. a) f(x, y) = sin(x - y) b) f(x, y) = sinx - sin y c) f(x, y) = sin(xy) VI d) f(x,y) = (1 -x2)(1-32) e) f(x, y) = et cosy f ) f ( x, y ) = 1+zz ty A B D