Answer :
I think your answer is going to be D. Congrats on finishing English!
Answer: D) multiple ideas are expressed using the same pattern and form.
Explanation: parallelism is a literary device that consists in the repetition of the grammatical structure of different words or phrases in a sentence or paragraph, in order to emphasize an idea or to create an impact in the audience. From the given options, the one that represents when a writer is using parallel structure (or parallelism), is the corresponding to option D: when multiple ideas are expressed using the same pattern and form.