In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. So, the only possible choice is B.
<h3><u><em>Carbon-14 has a half-life of 5,730 years. Taking one atom of 14C, this will either have decayed after 5,730 years, or it will not. But if this experiment is repeated again and again, it will be seen that the atom decays within the half life 50% of the time.</em></u></h3>
