A nurse is providing patient teaching to a patient who has been experiencing unstable angina.What will the nurse’s explanation of this condition include?

A coronary vessel has become completely occluded and is unable to deliver blood to the heart.

The pain is caused by a spasm of a blood vessel not just by the vessel narrowing.

Your body response to a lack of oxygen in the heart muscle is pain.

There is a serious narrowing of a coronary artery that is causing a reduction in oxygen to the heart.