Display the values of the function in two ways: (a) by sketching the surface z= f(x,y) and (b) by drawing an assortment of level curves in the function's domain. Label each level curve with its function value. f(x.y) = 4x +y? %3D a. Which of the following surface graphs represents f(x.y) 3 4x +y2? . C. b. Which of the following is the graph of the level curves of f(x.y)= 4x+y? O A. O B. z-4 z-4