Express the following as a function of 2 variables: The area of a parallelogram whose sides are vectors 3i and xi + yj. a) OA(x, y) = 6y b) OA (x, y) = 3/2 y c) OA(x, y) = 3/2 x d) O A(x, y) = 3 x e) OA (x, y) = 3y f) O None of the above