The correct answer is Carolus Linnaeus.
Carolus Linnaeus was the first who established the system of classification which includes four categories: class, order, genus and species. The modern classification is just an extension of this Linnaean system with the changes that were necessary as scientists learned more about life on Earth.
Binomial nomenclature (by Linnaeus) is still used as a way of giving scientific names to the organisms, where the first word is the name of the genus while the second one refers to the name of the species.
