Radioactive Dating: an Archaeologist Finds the ¹⁴C in a Sample

Radioactive dating: An archaeologist finds the ¹⁴C in a sample of 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 y. How old is the sample?

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