Below are three different arrangements of two mirrors near a source of
light. For each arrangement, a light ray is drawn from the source to the
first mirror. In which of these arrangements would the light eventually
travel parallel to, but in the opposite direction to, the original light. [This
type of device is called a retro-reflector.]
A.
B.
C.

In arrangement B) , mirrors are placed mutually perpendicular to each other . A retroreflector is a device or surface that reflects radiation back to its source with minimum scattering.When two mirrors are placed perpendicular to each other , and if a  light ray that strikes an object consisting of two mutually perpendicular reflective surfaces is reflected back exactly parallel to the direction to the source it came from. out of all arrangements , it can be observed that in arrangement B) , mirrors are placed mutually perpendicular to each other . hence , correct option will be option BTo learn more about reflective surface here :https://brainly.com/question/14618784SPJ1