[单选题]
The length of a spaceship is 10 m when it ishvsnzl d,/,r8 at rest. If the stv*fb dm0rf*qf 3+xfu0 5 y:b+/mfm hipaceship travels by you with a speed of 0.70c, 5: hyf0+ qf3+ud0bff*ibm tm x*fmv/r what length does it appear to you?
A. $5.5 \; m$
B. $7.1 \; m$
C. $12 \; m$
D. $18 \; m$
