By Dating Moon Rocks Astronomers Can Determine the Moon's Age

By dating Moon rocks astronomers can determine the Moon's age. How long ago did the Moon form?

A) The maria are about 3.8 billion years old, suggesting that the entire Moon was molten at that time, so that is its probable age.
B) The oldest rocks in the lunar highlands are about 4.3 billion years old, so that must be the age of the Moon.
C) Radioactive dating of Moon rocks brought back to Earth show that the Moon must be about 4.5 billion years old.
D) Because it cooled and solidified almost to its core, the Moon must be at least a billion years older than Earth. Its age, therefore, must be at least 5.5 billion years.