I think the answer is either
A. Why does Harry seem sad at the end of the passage.
or
D. Where will jack and Harry find work after the professor leaves?
Parallelism.
Metaphors and similes are used to relate one thing to another; this sentence is not doing that. Parallelism is when similar devices are used in sentences to convey one story.
The words in the sentence that make up the adjective phrase are from space. They modify aliens. Therefore D. is the correct answer.
They had to fight for their lives because people tried to hurt them because of their culture
