A point mass having mass M is moving with a velocity V at an angle $\Theta$ to the wall as shown in the figure. The mass undergoes a perfectly elastic collision with the smooth wall and rebounds. The total change (final minus initial) in the momentum of the mass is
(a) –2MVcos$\Theta \hat{j}$ (b) 2MV $\sin \Theta \hat{j}$ 
(c) 2MVcos$\Theta \hat{j}$ (d) –2MV $\sin \Theta \hat{j}$