[单选题]
The length of a spaceship is 10 m when it is at rest. If9o/hw/sea l )xu t ,mqr,mcu.0 the spaceship travels wz36*- c5b xmfs9zngt by you with a speed of 0.70c, what length does it appear to ycn tfxzg9bm z6-5 *sw3ou?
A. $5.5 \; m$
B. $7.1 \; m$
C. $12 \; m$
D. $18 \; m$
