Here is your answer:
Monologue is a long speech by a actor in a performance.
Soliloquy is a person speaking their thoughts out loud mainly happens in performances such as plays.
So the difference between these two things are that: "a monologue is a actors speech in a play but a soliloquy is a actors thoughts that are being said out loud in a play."
Hope this helps!
The main idea of the paragraph would be D. or " different societies have different ideas about the purpose of marriage. "
Deb pets tej
hope it was helpful