A mirror and a source of light are situated at the origin O and at a point on OX , respectively. A ray of light from the source strikes the mirror and is reflected. If the direction ratios of the normal to the plane are proportional to 1,−1,1 , then direction cosines of the reflected ray are
a. 31,32,32
b. −31,32,32
c. −31,−32,−32
d. −31,−32,32