The contour on the x-y plane, where the partial derivative of x2 + y2 with respect to y is equal to the partial derivative of 6y + 4x with respect to x is

The contour on the x-y plane, where the partial derivative of x2 + y2

1.	The contour on the x-y plane, where the partial derivative of x2 + y2 with respect to y is equal to the partial derivative of 6y + 4x with respect to x is
A.	y = 2
B.	x = 2
C.	x + y = 4
D.	x – y = 0
Answer» B. x = 2