65.

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

Item C: doing is the adverbial of the sentence, which means "NASA has 30 spacecrafts that have arrived at the red planet, prompting thinking - human voyage may no longer be the content of science fiction".

Item A: The front and back are complete sentences, which need to be connected by conjunctions, and A is excluded.

Item B/D: The latter sentence is not a modification of the previous noun red planet, and an attributive clause cannot be used. B/D is wrong.