Answer:
"Nothing Gold Can Stay," by Robert Frost, is a poem about the illusory nature of life.
This theme, that nothing of value (nothing gold) will last forever, is substantiated through the imagery of the poem.
Please update and Apply the sentences that are given so I can answer ;)
B) To give credit to the original authors
I would say B except (while A and C aren't correct for sure) it means OUTSIDE of earth's atmosphere----if it's "Earth-BOUND" it may not be IN Earth yet, but it's a real puzzler until you realize that so yes I would say B.