Glass has refractive index $\frac{3}{2}$ and water has refractive index $\frac{4}{3} .$ If the speed of light in glass is $2 \times 10^{8} \mathrm{~m} / \mathrm{s}$, then the speed of light in water will beA. $1.6 \times 10^{8} \mathrm{~m} / \mathrm{s}$B. $2.25 \times 10^{8} \mathrm{~m} / \mathrm{s}$C. $1.8 \times 10^{8} \mathrm{~m} / \mathrm{s}$D. $2 \times 10^{8} \mathrm{~m} / \mathrm{s}$