As the velocity of light increases,the refractive index of the medium decreases. Light enters from air to water having a refractive index of $4/3$. Find the speed of light in water. The speed of light in vacuum is $3 \times 10^{8} \text{ m s}^{-1}$.

• A
  $2.25 \times 10^{8} \text{ m s}^{-1}$
• B
  $2.00 \times 10^{8} \text{ m s}^{-1}$
• C
  $1.50 \times 10^{8} \text{ m s}^{-1}$
• D
  $3.00 \times 10^{8} \text{ m s}^{-1}$