If $200 \;MeV$ of energy is released in the fission of one nucleus of $^{235}_{92} U$, the number of nuclei that must undergo fission to release an energy of $1000\;J$ is :

Question

$$\begin {array} {1 1} (a)\;3.125 \times 10^{13} & \quad (b)\;6.25 \times 10^{13} \\ (c)\;12.5 \times 10^{13} & \quad (d)\;3.125 \times 10^{14} \end {array}$$