Question

If CPR is not performed, how many minutes will elapse before the brain becomes damaged from lack of oxygen?

Answer 1

If CPR is not performed, C. 4 minutes will elapse before the brain becomes damaged from lack of oxygen.
One minute isn't enough time - you can even hold your breath for one minute without fainting. Some people can even do it for 2 minutes.
Ten minutes is too long - you would be long dead. 

Answer 2

The answer is C - 4 minutes