Cyanosis is recognized by which of the following symptoms?

Cyanosis is a condition characterized by a bluish discoloration of the skin and mucous membranes, particularly noticeable in areas like the lips and fingertips. This bluish tint occurs due to an increased concentration of deoxygenated hemoglobin in the blood, indicating a lack of adequate oxygenation, which can result from various respiratory or circulatory disorders.

In this case, the identification of bluish coloration of the lips distinctly aligns with the medical definition and clinical presentation of cyanosis. Other options, such as yellow discoloration of the skin, redness of the face, and a greenish tint to the nails, do not describe the symptoms typically associated with cyanosis and may indicate completely different medical conditions. For instance, yellow discoloration may be indicative of jaundice, while redness can relate to inflammation or increased blood flow. Greenish tint can suggest bruising or other specific conditions. Thus, the correct answer clearly aligns with the defining characteristics of cyanosis.