If a Sample of the Radioactive Nuclide ¹³⁹Cs Has an Activity

If a sample of the radioactive nuclide ¹³⁹Cs has an activity of 0.0739 Ci,what is the instantaneous rate of decomposition of ¹³⁹Cs in terms of grams per second? The mass of ¹³⁹Cs is 138.9134 amu.(1 Ci = 3.700 × 10¹⁰ disintegrations/s,1 amu = 1.66054 × 10^-24 g)

A) ​7.39×10^-2 g/s
B) ​1.70×10^-23 g/s
C) ​8.53×10^-12 g/s
D) ​4.61×10^-14 g/s
E) ​6.31×10^-13 g/s