Answer Happy

What is the frequency of the emitted gamma photons (140-keV)?
(Note: Use Planck's constant h=6.6 x 10^-34 Js and the elemental
charge e=1.6 x 10^-19 C)
Can someone explain the process on how they got this answer pls?
Thank you
Solution: The correct answer is B. = A. The photon energy is 140 keV = 140 x 10^3 x 1.6 x 10-19 ) = 2.24 x 10-14 ]. This numerical value is inconsistent with the photon frequency derived as the ratio of 2.24 x 10-14 J and h = х 6.6 x 10-34 Js, according to the formula E = hf. B. The photon energy is 140 keV = 140 x 10^3 x 1.6 x 10-19 J = 2.24 x 10-14 J. The photon frequency is the ratio of 2.24 x 10-14 J and h = 6.6 x 10-34 Js, which is 3.38 x 1019 Hz. C. This numerical value is consistent with the inverse of the actual photon frequency. D. The photon energy is 140 keV = 140 x 10^3 x 1.6 x 10-19 ) = 2.24 x 10-14 ]. This numerical value is inconsistent with the photon frequency derived as the ratio of 2.24 x 10-14 J and h = 6.6 x 10-34 Is based on formula E = hf. eport r_