[单选题]
An electron is traveling at 0;)huefqx zijsp*xhh + z)aai012f y/+.85lfzp a 4p5l,yp6q+;mcm gus9/lm2 w2jc. What is its mass? (The rest mass is $9.11 \times 10^{-31} \; kg$.)
A. $1.4 \times 10^{-29} \; kg$
B. $7.2 \times 10^{-30} \; kg$
C. $1.7 \times 10^{-30} \; kg$
D. $2.4 \times 10^{-30} \; kg$
