The work function (ϕ) of some metals are listed below. The number of metals which will show the photoelectric effect when the light of 300 nm wavelength falls on the metal is:

Metal Li Na K Mg Cu Ag Fe Pt W
ϕ(eV) 2.4 2.3 2.2 3.7 4.8 4.3 4.7 6.3 4.75

A. 1
B. 2
C. 3
D. 4