 Of the following, which is the best plausible explanation for the behavior of the Earthen ships?
At the voyage's beginning eighty per cent of the fifteen-hundred-foot cylinder had been engines and fuel; but as the immense stores were spent and the holds became radioactively safe, the crew had spread out from its original cramped quarters. He said, with a touch of tolerant amusement, "What did you think might have happened to Earth? And we don't know what changes have taken place on Earth. That was the foreshortening along the time axis of a space ship approaching the speed of light. There is only one huge planet, twice the size of Jupiter, and like Jupiter utterly unfit to support a colony. If Procyon had possessed a habitable planet, we could have returned after an absence of not much over twenty years Earth time.
 900 years passed on Earth. The populations were different enough that the Quest III Earthens scared the current Earthen population.
 Since the Quest III trip promised to locate more planets, the current Earthens didn't trust them when they learned of their success because of how unlikely it was.  Since the Quest III trip promised to locate more planets, the current Earthens didn't trust them when they learned of their failure.  Since the Quest III trip promised to locate more natural resources, the current Earthens didn't trust them when they learned of their failure.  900 years passed on Earth. The populations were different enough that the Quest III Earthens scared the current Earthen population.