What is the correct geometric interpretation of fy (4, 5)? O The normal vector to the plane tangent to the surface z = f(:v, y) at the point (4) 5) O The slope of the line tangent to the surface z = f(a:, y) at the point (4, 5) O The slope of the line tangent to the surface 2: = f(:L', y) at the point (4, 5) along the line 33 = 4 G) The slope of the line tangent to the surface .3 = f(.', y) at the point (4, 5) along the line y = 5