How Do Astronomers Know That the Age of the Solar

Multiple Choice

How do astronomers know that the age of the solar system is about 4.5 billion years old?

A) radioactive dating of all the rocks on Earth shows that age
B) they estimate that age from the number of comets that are still located in the Kuiper Belt
C) radioactive dating of the primitive meteorites indicates they have that age (since they are left-over building blocks of the solar system)
D) they estimate the date from the number of impact craters on the Earth
E) they have the warranty book for each planet, and it tells you when the unit was manufactured