Each of the following is true about the potassium-argon method of dating EXCEPT:
A) Fossils found in the Rift Valley of eastern Africa can be dated using the potassium-argon method.
B) The half-life of a radioactive isotope refers to the average amount of time until half of the atoms in the sample have decayed.
C) Volcanic ash initially only contains radioactive potassium, which over time decays into argon.
D) The older a volcanic ash layer is, the less argon is found within it.