This chart show the amount of radioactivity measured from three unknown isotopes. Which statement describes each of the isotopes?

Isotope A was measured at day 24, Isotope B was measured at day 6, and Isotope C was measured at day 10.
Isotope A was measured at day 18, Isotope B was measured at day 4, and Isotope C was measured at day 5.
Isotope A was measured at day 24, Isotope B was measured at day 8, and Isotope C was measured at day 20.
Isotope A was measured at day 30, Isotope B was measured at day 6, and Isotope C was measured at day 10.