[单选题]
A spaceship takes a nonstop journey to a planet and returns in 10 2fikf4izqn m-wt9 3 hxwf676m hours*z0.msh9gx5 uh/wcdo according to a clock on the spaceship. If the speed of the spaceship.9s c/hgu0xw hmod5*z is 0.80c, how much time has elapsed on the Earth?
A. $3.2 \; h$
B. $7.0 \; h$
C. $15 \; h$
D. $17 \; h$
