A light wave described by $$E=60[\sin(3\times10^{15})t+\sin(12\times10^{15})t]$$ (in SI units) falls on a metal surface of work function 2.8 eV. The maximum kinetic energy of ejected photoelectron is (approximately) ___ eV. $$(h=6.6\times10^{-34}J.s\text{ and }e=1.6\times10^{19}C)$$

A

7.8

B

6.0

C

3.8

D

5.1