[单选题]
What is the momentumy4v/m /a ys;a(f+wuu nmj9 de6 i4kky64q0f zf7ou n .ven $kg \cdot m/s$ of a proton when it is moving with a speed of 0.60c?
A. $1.2 \times 10^{-19} \; kg \cdot m/s$
B. $1.5 \times 10^{-19} \; kg \cdot m/s$
C. $3.0 \times 10^{-19} \; kg \cdot m/s$
D. $3.8 \times 10^{-19} \; kg \cdot m/s$
