A radioactive isotope $^{14}\text{C}$ emits beta-particles. A sample of this isotope is kept for a time equal to its half-life. Which two quantities fall to half of their starting values during this interval?
- Athe decay rate and the number of protons
- Bthe mass of the sample and the number of $^{14}\text{C}$ nuclei
- Cthe number of $^{14}\text{C}$ nuclei and the decay rate
- Dthe number of protons and the mass of the sample