Which of the following may indicate that a person is in cardiac arrest?

The correct answer encompasses all the options, highlighting that each one individually indicates potential signs of cardiac arrest.

When a person is in cardiac arrest, their heart is no longer effective at pumping blood, which can lead to several critical symptoms. The absence of breathing is a primary indicator; when the heart stops, the lungs cease functioning, leading to a lack of respiratory activity.

Unresponsiveness is another critical sign, as an individual in cardiac arrest will not be conscious or able to respond to stimuli due to inadequate blood flow to the brain.

Pale or bluish skin, often referred to as cyanosis, occurs because of insufficient oxygen in the blood when circulation has stopped, resulting in a change in the skin's color.

Each of these signs points distinctly toward a state of cardiac arrest, making it vital for anyone observing these symptoms to respond quickly by calling emergency services and initiating CPR if properly trained. The comprehensive nature of these signs confirms the seriousness of the situation and underscores the necessity for immediate action.