Carbon-14,which Is Present in All Living Tissue,radioactively Decays Via a First-Order

Carbon-14,which is present in all living tissue,radioactively decays via a first-order process.A one-gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per minute.If the half-life for carbon-14 is 5715 years,how old is a wood sample that gives a rate for carbon-14 decay of 11.9 counts per minute?

A) 5) 3 × 10² yr
B) 7) 6 × 10² yr
C) 1) 1 × 10³ yr
D) 9) 4 × 10³ yr