The velocity potential function is given by an expression $$\psi = -\frac{xy^3}{3} - x^2 + \frac{x^3y}{3} + y^2$$ The velocity component in X-direction is:
(a) $$xy^2 - \frac{x^3}{3} - 2y$$
(b) $$\frac{y^3}{3} + 2x - x^2y$$
(c) $$3x^2y + 2x - xy^2$$
(d) $$x^3y^2 + 2x^2 - y^2x$$

A

(a)

B

(b)

C

(c)

D

(d)