[单选题]
A spaceship takes a nonstop journey to au wp7gx1kj*mp3 8top0 planet and returns in 10 hours accordd8oqep5+*nl hing to a clock on the spaceshipedn 85p+lqo* h. If the speed of the spaceship is 0.80c, how much time has elapsed on the Earth?
A. $3.2 \; h$
B. $7.0 \; h$
C. $15 \; h$
D. $17 \; h$
