Atoms And Nuclei

Consider that in a fission of a single Plutonium ( $\mathrm{Pu}^{239}$ ) atom 207 MeV energy is released. Assuming all atoms of Plutonium undergo fission, which of the following options is the closest estimate of the amount of Plutonium required for a 20,000 units of TNT explosion? (1 unit of TNT $=4.184 \times 10^9 \mathrm{~J}, 1 \mathrm{eV}=1.6 \times 10^{-19} \mathrm{~J}$ )