Suppose the Time Taken for Light to Bounce to and Fro

Multiple Choice

Suppose the time taken for light to bounce to and fro between the parallel mirrors of a light clock is 1 second,in the frame of reference of the light clock.As seen by another observer moving at high speed at right angles to the to-and-fro motion of the bouncing light,the time taken would be

A) also 1 second.
B) less than 1 second.
C) more than 1 second.