Final answer:
The correct option is a. Cyanosis is a bluish or grayish discoloration of the skin, nail beds, and/or lips that occurs when there is a lack of oxygen in the blood. It can be a sign of respiratory problems or heart conditions.
Step-by-step explanation:
Lack of oxygen in the blood may be evidenced by a bluish or grayish discoloration of the skin, nail beds, and/or lips known as cyanosis. Cyanosis is a condition that occurs when there is a decrease in the amount of oxygenated hemoglobin in the blood.
When the oxygen levels are low, the blood appears bluish or purple. This can be a sign of respiratory problems or heart conditions. Cyanosis is a bluish or grayish discoloration of the skin, nail beds, and/or lips that occurs when there is a lack of oxygen in the blood. It can be a sign of respiratory problems or heart conditions.