Atoms of carbon-14 are radioactive. They decay into atoms of the element nitrogen. Suppose that a sample of rock is taken from a fossil. The sample has 1000 atoms of carbon-14 and 1000 atoms of nitrogen.

If carbon-14 has a half-life of 57-- years, how old is the fossil?

A. 11,400 years old
B. 5700 years old
C. 2850 years old
D. 17,100 years old.