The correct answer is: A. 5 April
National Science Day is celebrated in India on 28 February every year to commemorate the discovery of the Raman Effect by Indian physicist Sir C. V. Raman on 28 February 1928. The Raman Effect is the scattering of light by a substance, and the change in the wavelength of the scattered light as a result of the interaction with the substance. Raman was awarded the Nobel Prize in Physics in 1930 for his discovery.
The Raman Effect is a very important phenomenon in physics and chemistry, and it has many applications in a variety of fields, including spectroscopy, materials science, and biology. It is also used in a number of industrial processes, such as the production of semiconductors and pharmaceuticals.
The Raman Effect is a very beautiful and elegant phenomenon, and it is a testament to the brilliance of Sir C. V. Raman. His discovery has had a profound impact on our understanding of the physical world, and it continues to be used in a variety of fields to this day.
The other options are incorrect because they are not the dates on which National Science Day is celebrated in India.