A driver wears polarising sunglasses whose transmission axis is vertical. While driving on a dry road in bright sunshine, the glare from the road surface is greatly reduced. Which statement best explains this observation?
(a) Light reflected from the road is mainly vertically polarised; the vertical-axis sunglasses therefore block it, reducing glare.
(b) Any polarising sheet, irrespective of orientation, cuts the intensity of incident light roughly to one-half, so glare diminishes.
(c) Light reflected from the road at the appropriate angle is mainly horizontally polarised and is blocked by the vertically oriented sunglasses.
(d) Light reflected from the road becomes circularly polarised and is almost completely absorbed by the vertically oriented polariser.