In a radioactive sample, 40K19 nuclei either decay into stable 40Ca20 nuclei with decay constant 4.5 × 10–10 per year or into stable 40Ar18 nuclei with decay constant 0.5 × 10–10 per year. Given that in this sample all the stable 40Ca20 and 40Ar20 nuclei are produced by the 40K19 nuclei only. In time t × 109 years, if the ratio of the sum of stable 40Ca20 and 40Ar18 nuclei to the radioactive 40K19 nuclei is 99, the value of t will be,
(A) 1.15
(B) 9.2
(C) 2.3
(D) 4.6
