Absolute refractive index of glass and water is $\frac{3}{2}$ and $\frac{4}{3}$ respectively. If the speed of light in glass is $2 \times 10^{8} \mathrm{~m} / \mathrm{s}$, the speed of light in water is :

The question requires the use of the formula for absolute refractive index and the relationship between the speed of light in a medium and its refractive index. The correct answer is $\frac{9}{4} \times 10^{8} \mathrm{~m} / \mathrm{s}$, which is option A.