When Dealing with Radioactive Decay of Materials, We Often Read

Multiple Choice

When dealing with radioactive decay of materials, we often read about the age of a particular rock. What is meant by the age of a rock?

A) It is the age of the atoms within the rock.
B) It is the time since the rock was formed and the elements within the rock were isolated with definite abundance ratios.
C) It is the age of the planet or moon on which the rock is found.
D) It is actually a misnomer, since only radiogenic elements can be dated. A rock can be dated only if it is a pure radiogenic element.