An Archaeologist Finds the ¹⁴C in a Sample of 3

An archaeologist finds the ¹⁴C in a sample of 3.10 g of material to be decaying at 107 counts per second.A modern 1.00-g sample of the same material decays at 151 counts per second.The half-life of ¹⁴C is 5730 years.How old is the sample?

A) 12,200 years
B) 8460 years
C) 25,100 years
D) 12,600 years