When in hydrogen like ion, electron jumps from n = 3, to n = 1, the emitted photon has frequency `2.7 xx 10^(15)Hz`. When electron jumps from n = 4 to n = 1, the frequency is
A. `1.6 xx 10^(15)Hz`
B. `2.8 xx 10^(15)Hz`
C. `6.4 xx 10^(15)Hz`
D. `4.8 xx 10^(15)Hz`