Answer : 3. "CV Raman"
Explanation :

Sir Chandrasekhara Venkata Raman, discovered on 28 February 1928, that when a beam of coloured light entered a liquid, a fraction of the light scattered was of a different color, dependent on material property. This radiation effect of molecular scattering of light bears the name of ‘Raman Effect’, from which many applications in photonic communications and spectroscopy evolved. The Raman Effect is the process of scattering light particles by molecules of a medium.