The line is an example of a direct quotation. That is when a quotation by someone is unchanged and presented in its entirety. Of course, it's a part of a larger speech, but it's unchanged and can be as such analyzed for various things that the linguists would be searching for.
The answer to this is reins, it is reins because this is all filler for you to allow me to put down this answer, its reins.
The answer should be D) because A) is not tension, B) is really not tension, and C) is not suspense either so I would go with D) since we don't know what they're talking about and why so quiet.
He kills MacDuff"s family