A proton has kinetic energy E = 100 keV which is equal to that of a photon. The wavelength of photon is \[{{\lambda }_{2}}\] and that of proton is \[{{\lambda }_{1}}.\] The ration of \[{{\lambda }_{2}}/{{\lambda }_{1}}\] is proportional to

• A. \[{{E}^{2}}\]
• B. \[{{E}^{1/2}}\]
• C. \[{{E}^{-1}}\] 
• D. \[{{E}^{-1/2}}\]