[单选题]
How fast would a rocketn02t0c 5q px 1xz*xt4x ovm(rk ship have tqy,g dmx-: p5 wih0 9jdltc/c7o move to contract to half of its proper length (as observed by a stationary 5c mdti0jqp-9/ d:yhwclx7 g,object)?
A. $0.50 \; c$
B. $0.65 \; c$
C. $0.78 \; c$
D. $0.87 \; c$
