A small coin is resting on the bottom of a beaker filled with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure) <br> <br> How fast is the light traveling in the liquid ?

Question

( A ) $1.8 \times 10^8 m/s$
( B ) $3.0 \times 10^8 m/s$
( C ) $2.4 \times 10^8 m/s$
( D ) $1.2 \times 10^8 m/s$