Final answer:
The correct answer is 4) 12 mins. Brain damage becomes a risk after 12 minutes without CPR in cases of cardiac arrest.
Step-by-step explanation:
The correct answer is 4) 12 mins.
When a person experiences a cardiac arrest, the flow of oxygenated blood to the brain is interrupted. Without oxygen, brain cells begin to die, which can lead to brain damage. Brain death is likely to occur after about six minutes without oxygen, except in exceptional circumstances such as cold water immersion. However, even in cold water immersion cases, brain damage becomes a risk after 12 minutes without CPR.