The energy from the radioactive decay of tritium is used to illinate exit signs that are posted in many buildings. The manufacturer adds 8 times as much tritium to the signs as is required to meet the brightness that fire codes require. If tritium decay is first order and the half-life of tritium is 12.5 years, how long will the signs meet the fire code?
A. 25yrs
B. 12.5yrs
C. 37.5yrs
D. 50.0yrs
E. none of these