What was the approximate activity of the plutonium source at the start of the mission?
A. \(2 \times 10^{21} \mathrm{~Bq}\)
B. \(2 \times 10^{19} \mathrm{~Bq}\)
C. \(2 \times 10^{17} \mathrm{~Bq}\)
D. \(2 \times 10^{15} \mathrm{~Bq}\)
E. \(2 \times 10^{13} \mathrm{~Bq}\)

The Curiosity rover sent to explore the surface of Mars has an electric generator powered by heat from the radioactive decay of \({ }^{238} \mathrm{Pu}\), a plutonium isotope that decays by alpha emission with a half-life of 88 years. At the start of the mission, the generator contained \(9.6 \times 10^{24}\) nuclei of \({ }^{238} \mathrm{Pu}\).