[单选题]
How fast would a roc9/ .wbdp1sex dfv1fa9ket ship have to move to contre0f nz96vuj*8 zys rlt i63,jyact to half of its proper length (as observed b ,sv 6* 3eirnt8jz0zly6u9jfyy a stationary object)?
A. $0.50 \; c$
B. $0.65 \; c$
C. $0.78 \; c$
D. $0.87 \; c$
