Light Intensity ( I )Can Be Described as the Power $\pi$

Multiple Choice

Light intensity ( I ) can be described as the power emitted by a light source (P) over a given area (in m²) .Suppose a 100-watt mercury vapor lamp emits 365.4 nm photons equally in all directions.At a distance of 1.450 m,how many photons hit per square meter per second? (1 watt = 1 J/s; I = P/Area = P/4 $\pi$ d ²,where d is the distance)

A) 5 $\times$ 10⁷ photons
B) 7 $\times$ 10⁹ photons/m² .s
C) 9 $\times$ 10¹⁶ photons/m² .s
D) 7 $\times$ 10¹⁸ photons/m² .s
E) 6 $\times$ 10¹⁹ photons/m² .s