For each of the following vector fields F , decide whether it is conservative or not by computing the appropriate first order partial derivatives. Type in a potential function f (that is, Vf = F) with f(0, 0) = 0. If it is not conservative, type N. A. F(x, y) = (8x - 7y)i + (-7x + 6y)j f(I, y) = B. F(x, y) = 4yi + 5xj f(I, y) = C. F(x, y) = (4siny)i + (-14y + 4x cosy)j f(I, y) = Note: Your answers should be either expressions of x and y (e.g. "3xy + 2y"), or the letter "N"