The correct answer is C. D. Iwanowski.
Dmitri Ivanovsky was a Russian botanist who discovered viruses in 1892. He was studying tobacco mosaic disease and found that the disease could be transmitted through a filter that could not pass bacteria. This led him to believe that the disease was caused by a non-living agent, which he called a “filterable virus.”
V.M. Stanley was an American biochemist who crystallized tobacco mosaic virus in 1935. This was the first time that a virus had been crystallized, and it provided strong evidence that viruses were not simply chemicals, but rather living organisms.
Stanley Miller was an American chemist who conducted the MillerâUrey experiment in 1953. This experiment showed that organic molecules, the building blocks of life, could be formed from inorganic molecules under conditions similar to those thought to have existed on early Earth.
Karpenchenko was a Soviet botanist who discovered a new type of virus in 1940. This virus, which he called the Karpenchenko virus, was found to infect plants.
In conclusion, the correct answer is C. D. Iwanowski. He was the first person to discover viruses, and his work was essential to our understanding of these fascinating and important organisms.