When radiation is incident on a photoelectron emitter , the stopping potential is found to be `9 volts` . If `e//m` for the electrons is `1.8 xx 10^(11) C kg^(-1)` the maximum velocity of the ejected electrons is
A. `6 xx 10^(5) ms^(-1)`
B. `8 xx 10^(5) ms^(-1)`
C. `1.8 xx 10^(6) ms^(-1)`
D. `1.8 xx 10^(5) ms^(-1)`