Hint: Cathode rays are the rays emitted from the cathode of the high-vacuum-tube. It was discovered. There are streams of the electrons in a discharge tube. In 1897, it was confirmed that the cathode rays are composed of the negatively charged particle known as electrons.
About the discovery of the cathode rays, actually it was two German physicists named Julius Plücker and Johann Wilhelm who firstly observed these rays in 1869. But they were named by someone else named Eugen Goldstein in 1876.
And after all this happened, a British physicist named J.J. Thomson (in 1897) came to the conclusion that these cathode rays are composed of some unknown negatively charged part vile which were later known as electrons.
Here in the given question any of the options is not showing the mention of any of the above scientists other than the J.J. Thomson. So, regarding this situation the correct answer is J.J. Thomson.
So, the correct answer is “Option D”.
Process of generation of the cathode tube-
To understand the formation of the cathode rays we will take an activity example as follows-
If we take an evacuated glass tube and we put two electrodes (named cathode and anode). Now we apply some voltage across the electrodes. Then we will see that there is glow at the opposite side of the negative electrode. This glow is due to the emission of the electrons from the cathode. Hence, we see that the discovery of the electrons was done as a constituent of the cathode rays. One of the examples of the application of the cathode ray is the image formation in the televisions by the use of cathode ray tubes.