If an Electron,initially at Rest,is Accelerated Through a Potential Difference $\times$

Multiple Choice

If an electron,initially at rest,is accelerated through a potential difference of 180 kV,the relativistic mass of the electron is

A) 12.3 $\times$ 10^-31 kg
B) 9.11 $\times$ 10^-31 kg
C) 16.2 $\times$ 10^-31 kg
D) 5.90 $\times$ 10^-31 kg
E) infinite