[单选题]
An electron is traveling at 0.85c. What is its mass? (Thelrzy.evs5/va no:k7qv51 - lg +r4obe re5ay,1m /ru6nw12idmx,uk.ys b i+ tckt 7m;f wst 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. $2.4 \times 10^{-30} \; kg$