Binomial nomenclature means

Binomial nomenclature is the formal system of naming species of living things, popularized by Carl Linnaeus. According to this system:

• Biological names are generally in Latin and written in italics (when printed) or underlined (when handwritten).
• The name consists of two parts: the first word denotes the Genus (generic name), and the second word denotes the Specific Epithet (species name).
• The genus name starts with a capital letter, while the species name starts with a small letter.

For example, in Homo sapiens, Homo is the genus and sapiens is the species. Options B, C, and D are incorrect as biological nomenclature does not use parental names, orders, or phyla as the primary two-part naming components.