A horizontal ray of light passes through a prism of refractive index 1.5 and apex angle 4° and then strikes a vertical plane mirror placed to the right of the prism. If after reflection, the ray is to be horizontal, then the mirror must be rotated through an angle
(A) 1° clockwise
(B) 1° anticlockwise
(C) 2° clockwise
(D) 2° anticlockwise
