The carbon dating method discussed in the video is useful for determining the ages of living materials that are a few thousand or a few tens of thousands years old. K-40 decays into Ar-40 with a half life of 1.2 billion years, making it suitable for estimating the age of very old astronomical objects (for the simplicity of this problem, we assume that this is the only possible decay for K-40). Assume that when a particular rock formed, it had a decay rate of 0.061 decays/sec/g, and it now has a decay rate of 0.015 decays/sec/g. Using the estimation method in the video, which is the closest estimate for the age of this rock? a. 0.3 billion years
b. 0.6 billion years
c. 1.2 billion years
d. 2.4 billion years
e. 4.8 billion years