What should be done if a person becomes unresponsive while experiencing breathing problems?

When a person becomes unresponsive while experiencing breathing problems, initiating cardiopulmonary resuscitation (CPR) is crucial. This is because unresponsiveness often indicates that the person is not breathing adequately or may have ceased breathing altogether. CPR is designed to maintain blood circulation and provide oxygen to vital organs, particularly the brain, in such emergencies.

In this scenario, performing CPR helps supply oxygenated blood to the heart and brain until emergency medical services can arrive or the person begins to breathe normally again. The other options are not appropriate responses. Shaking the person may not effectively address the underlying issue of their unresponsiveness and could potentially worsen the situation. Leaving the person alone is unsafe, as they may need immediate assistance. Providing water isn't advisable, as an unresponsive individual may be at risk of choking or aspirating the liquid. Thus, performing CPR is the correct and life-saving action in this context.