Electron from a Heated Filament in an Electron Gun Travels $1.5 \times 105 \mathrm{~m} / \mathrm{s}$

electron from a heated filament in an electron gun travels with constant acceleration to the tip of the gun, where it is emitted. If the final speed of the electron is $1.5 \times 105 \mathrm{~m} / \mathrm{s}$ , the length of the gun from filament to tip is $1.25 \mathrm{~cm}$ , and the electron started from rest, what was the acceleration of the electron?

A) $9.0 \times 10^{9} \mathrm{~m} / \mathrm{s}^{2}$
B) $1.8 \times 1012 \mathrm{~m} / \mathrm{s}^{2}$
C) $9.0 \times 1011 \mathrm{~m} / \mathrm{s}^{2}$
D) $6.0 \times 10^{6} \mathrm{~m} / \mathrm{s}^{2}$
E) $9.0 \times 1010 \mathrm{~m} / \mathrm{s}^{2}$
F) $1.8 \times 10^{9} \mathrm{~m} / \mathrm{s}^{2}$