reason
Explanation:
because it fits why because on the reason is the one which is fitting
You didn't put a passage for this question if you send it I can help
Answer:
In her book, Nguyen discusses how she escaped from the Viet Cong, how she came to America, and how she adjusted to American life.
Explanation:
how + subj. - verb - used consistently for all three clauses
The answer to you're question is D