The correct answer is Robert Koch.
He was a German scientist and is globally known as one of the fathers of microbiology and bacteriology. He is famous for his work with anthrax, finding out the causative agent of the fatal disorder to be Bacillus anthracis. He received a Noble prize for his work in 1905. He also gave four postulates known as Koch's postulates.
The four characteristics that were formulated by Robert Koch to determine the causative agent of a specific disorder are:
1. The pathogen or microorganism must be must be found in all the cases of the disorder.
2. The pathogen can be withdrawn from the affected host and can be developed in pure culture.
3. The pathogen from the pure culture must result in a disease when incorporated into a vulnerable, healthy laboratory animal.
4. The pathogen must be reisolated from the novel host and demonstrated to be similar to the originally inoculated pathogen.