Gamma-ray bursts in the universe are emitted from objects that emit pulses of gamma rays with high energies. The frequency of the most energetic bursts has been measured at around 1.2 x 10^15 Hz.
What is the wavelength of these gamma rays?

A 4.5 x 10^-7 m
B 2.5 x 10^-7 m
C 3.5 x 10^-7 m
D 1.5 x 10^-7 m