What happens when two polarizers are placed in a straight line, one behind the other?
A. They allow light to pass only if they are polarized in exactly the same direction.
B. They block all light if they are polarized in exactly the same direction.
C. They allow light to pass only if their directions of polarizations are exactly 90° apart.
D. They block all light if their directions of polarizations are exactly 90° apart.
E. They block all light if their directions of polarizations are either exactly the same or exactly 90° apart.