Which statement is correct about the half-life of a radioactive isotope?
- AHalf-life changes as the isotope decays.
- BHalf-life is the time it takes for the nucleon number of the isotope to halve.
- CHalf-life is half the time it takes for the number of nuclei of the isotope to decrease to zero.
- DHalf-life is the time it takes for the number of nuclei of the isotope to decrease by half.