Question

Dmitry Ivanovsky reported the existence of the virus in
(a) Tobacco
(b) Potato
(c) Wheat
(d) None of the above

Answer 1

Dmitry Ivanovsky was a Russian botanist who investigated a disease caused in plants by the virus named TMV. But he didn't know about viruses at that time. Later another microbiologist Beijernick acknowledged his findings and named these pathogens viruses.

Complete step by step answer:
Dmitry Ivanovsky reported that infected leaves of tobacco contain the pathogenic virus in them. He was a Russian botanist who discovered viruses and is one of the founders of virology. He wrote about his findings in the article named "On Two Diseases of Tobacco" and the dissertation "Mosaic Disease in Tobacco

Additional Information: Ivanovsky was a botanist in Russia who studied at the University of Saint Petersburg under Andrel Famintsyn. He was sent to investigate a tobacco disease in Ukraine and Bessarabia which was causing great damage to the tobacco plantations. After Ukraine and Bessarabia, he was again assigned for the same tobacco disease case in the Crimea region three years later. He later found out that these all cases have a similar pathogen which didn't have the characteristics of a bacteria. It was some kind of extremely minuscule agent which was capable of permeating porcelain Chamberland filters. These were actually the tobacco mosaic virus of the genus Tobamovirus. He wrote about the whole situation and his findings in an article and a dissertation.
Later in 1898, a Dutch microbiologist Beijernick replicated Ivanovsky's experiment and named the infection agent as Virus.
So, the correct answer is Tobacco.

Note: Although Dmitry Ivanovsky is known as the discoverer of the virus, it is Beijernick who actually discovered it independently and named these as viruses. Beijernick was a Dutch microbiologist and botanist. He is also the discoverer of nitrogen fixation and the phenomenon of bacterial sulfate reduction which is a form of anaerobic respiration. He also invented the enrichment culture. This is one of the methods of studying microbes in the environment.