The correct answer is: A. Francesco Cetti.
The term “taxon” was first used by Francesco Cetti in 1777. He used it to refer to a group of organisms that share a common ancestor. The term was later adopted by other biologists and is now used to refer to any group of organisms, whether it is a species, genus, family, or order.
Adolf Meyer-Abich was a German botanist who lived from 1828 to 1908. He is best known for his work on the flora of the Alps. He did not use the term “taxon” in his work.
Nathan Cobb was an American zoologist who lived from 1859 to 1932. He is best known for his work on the nematodes. He did not use the term “taxon” in his work.
Gregor Mendel was an Austrian monk who lived from 1822 to 1884. He is best known for his work on genetics. He did not use the term “taxon” in his work.