[单选题]
A spaceship takes a nonstot6vx 2(s zos+i/iznn :s-2vx6qjv cq )p journey to a plaje i),e(nsjg/ net and returns in 10 hours according to a clock on the spaceship. If the speed of the spaceship is 0.80c, how much time has elapsed onn /g,ej)j(ise the Earth?
A. $3.2 \; h$
B. $7.0 \; h$
C. $15 \; h$
D. $17 \; h$
