Monochromatic light of frequency $6.0 \times 10^{14}$ Hz is produced by a laser. The power emitted is $2 \times 10^{-3}$W. The number of photons emitted, on the average, by the source per second is :-

Question

( A ) $5 \times 10^{16}$
( B ) $5 \times 10^{15}$
( C ) $5 \times 10^{17}$
( D ) $5 \times 10^{14}$