[单选题]
How fast would a rocyr, v m0wsjl,ff::kf u )-hzf(kx n:y,d7 6ae,rox eipzj7ony*(5in; zet ship have to move to contract to half of its proper length (as observez7noe6no (;n5 jiaxyidezp7 ,,yx*: rd by a stationary object)?
A. $0.50 \; c$
B. $0.65 \; c$
C. $0.78 \; c$
D. $0.87 \; c$
