A Sample of the Radioactive Isotope ⁹⁰Sr Was Found to Decay

A sample of the radioactive isotope ⁹⁰Sr was found to decay by a first order process. If 1.00% of the original 2.5×10 ^{- 3} gram sample decays in 0.406 years, determine the half-life of ⁹⁰Sr.

A) 20.3 yr
B) 1.61×10⁴ yr
C) 2.46 yr
D) 19.9 yr
E) 28.0 yr