The correct answer is B. It is important to know that learning CPR from the movies is a bad idea. Very often they show us 3 or 5 chest compressions, which probably looks more dramatic, but in reality, we need a lot more. We need to build enough pressure in the blood vessels so that the oxygenated blood reaches the brain and this is not possible if we stop every 3 or 5 compressions. Also every time we stop to give a breath we need to do it quickly because every second without chest compressions means less oxygen for the brain, which lowers the chances of survival.