$A$ light ray of frequency '$v$' and wavelength '$\lambda$' enters a liquid of refractive index $\frac{3}{2}$. The ray travels in the liquid with:

• A
  frequency $v$ and wavelength $\left(\frac{2}{3}\right) \lambda$
• B
  frequency $v$ and wavelength $\left(\frac{3}{2}\right) \lambda$
• C
  frequency $\left(\frac{3}{2}\right) v$ and wavelength $\lambda$
• D
  frequency $\left(\frac{2}{3}\right) v$ and wavelength $\left(\frac{2}{3}\right) \lambda$