Answer:
"There are two in each room," the nurse remarked over her
shoulder
"Two what?" asked Marian without thinking.
Step-by-step explanation:
Dialogue is when a character speaks to another character. A character can speak to themselves (monologue). Marian and the nurse share one line remarks to one another, which is the only dialogue in this passage. The rest is imagery/narration.
Dialogue is identified by "quotation marks".
Quotation marks most often indicate dialogue, but do have other uses.
Such as for "Book Titles", or sarcasm.