Answer:
The correct answer would be a. a two-word system for naming organisms by using the genus and species.
Binomial nomenclature or two name naming system refers to the formal system of naming a living organism.
This system gives a two words name to specific species. Both the words are generally Latin in origin.
The first word always starts with a capital letter and represent the genus name of an organism.
The second name starts with the small letter and represents the species name of the organism.
The scientific name is always written in italics when typed or printed or underlined separately if it is handwritten.
For example, the scientific name of human is Homo sapiens. The Homo represents the genus whereas sapiens represents the species.