[单选题]
Starting from rest, a proton falw5q7lflyio2z44;du sq yh4) ols through a potential d7 v 2a 6w)axws7w7sqixkvao (.ifference of 1200 V. What speed does it acquiw6avav .x7osq 7 2w(axw7k)sire?
A. $1.2 \times 10^{5} \; m/s$
B. $2.4 \times 10^{5} \; m/s$
C. $3.6 \times 10^{5} \; m/s$
D. $4.8 \times 10^{5} \; m/s$
