What is the yellow room in the book the compound

The yellow room is a place in the compound in which three children live, who were born during the time of their living in the compound. They aren't referred to as children, rather as supplements, because they are intended to become food one day for the adults who live in the compound.

D) only knows what Utterson and Poole know, which builds suspense.

Explanation: In the given excerpt from "The Strange Case of Dr. Jekyll and Mr. Hyde" by Robert Louis Stevenson, we can see a conversation between Mr. Utterson and Poole (Dr. Jekyll's lawyer and butler respectively) about the change on the voice and in the general behavior of Dr. Jekyll. This excerpt is told from a limited third-person perspective, that means that the reader only know what Utterson and Poole know, and this helps to build suspense.