K = (1/2)mv^{2} = p^{2}/2m (since p = mv)

Therefore p = (2mK)^{1/2}

l = h/p = h/(2mK)^{1/2} = (6.63X10^{-34}Js)/[(2)(9.11X10^{-31}
kg)(6.0X10^{21} J)]

= 6.34X10^{-9} m

For the photon

E = hc/l = (6.63X10^{-34}Js)(3.0X10^{8
}m/s)/6.34X10^{-9} m = 3.14X10^{-17} J

Answer is D