The work function of a metal surface is 2.3eV. Four monochromatic beams of equal intensity having wavelengths 300 nm (A), 400 nm (B), 500 nm (C) and 600 nm (D) are separately allowed to fall on the surface. hc=1240eV⋅nm. Arrange the beams in the decreasing order of the stopping potential produced.
a) D>C>B>A
b) A>C>B>D
c) A>B>C>D
d) A>B>D>C