A photon of wavelength 200 nm strikes the surface of a metal causing an electron to be ejected with kinetic energy of 4.3×10^-19 J. What was the

A photon of wavelength 200 nm strikes the surface of a metal causing an electron to be ejected with kinetic energy of 4.3×10^-19 J. What was the threshold frequency of the metal?
a) 8.5 x10^14 Hz
b) 1.6 x10^12 Hz
c) 5.2 x10^15 Hz
d) 1.2 x10^13 Hz
e) 7.4 x10^15 Hz