$$K_1$$ and $$K_2$$ be the maximum kinetic energies of photoelectrons emitted from a surface of a given material for the light of wavelength $$\lambda_1$$ and $$\lambda_2$$, respectively. If $$\lambda_1 = 2\lambda_2$$ then the work function of material is given by :

A

$$K_2 + 2K_1$$

B

$$2K_2 - K_1$$

C

$$K_1 - 2K_2$$

D

$$K_2 - 2K_1$$