Please answer the following question: Fact 1: Brain cells die quickly if their oxygen supply is cut off. Fact 2: Brain cells begin to die as soon as the heart stops pumping oxygen. Given the two facts above, answer the question "What can cut off the oxygen to cells?" with the following options: - Sulfur dioxide - oxygen atoms - the heart stopping - massive damage - smoking pipes - water - hair - cigarettes
A:
the heart stopping