In Acer rubrum 'Red Sunset', Red Sunset is the cultivar name.

• A. Red Sunset is the cultivar name
• B. Red Sunset is the species name
• C. Red Sunset is the genus name
• D. Red Sunset is the family name

Answer: (A)

In plant naming, a cultivar is a cultivated variety selected for distinct traits and given its own name after the species. In Acer rubrum 'Red Sunset', the part in single quotes is the cultivar name, identifying a specific, reproducible form of the species. The genus is Acer, and the species name is rubrum, which together name the red maple. The cultivar label is not a taxonomic rank like genus or species; it’s a horticultural designation used to maintain a desirable form through propagation. The family name would be Sapindaceae, which is a higher taxonomic level and separate from the cultivar label.