The correct option is A 3.125×1016
Here, we can write,
Power=Energy producedtime
=No. of fissions×Energy released in one fissiontime
=No. of fissions per sec.×Energy released in one fission
⇒1000×103=n×200×106×1.6×10−19
∴ n=3.125×1016 per sec.
Hence, (A) is the correct answer.