In a barber’s shop, two plane mirrors are placed:
(a) perpendicular to each other
(b) parallel to each other
(c) at an angle of 60° between them
(d) at an angle of 45° between them.

(b) parallel to each other

Reason — In a barber’s shop, in order to see the hairs at the back of the head two plane mirrors are placed parallel to each other at the front and at the back of the viewer.