I believe that the correct answer is D because it is already stated once that they need the sirens so it is giving us a fact that has already been stated.
I think the answer is
We’re
The clause <em>who bought the coat </em>is used as an adjective subordinate clause because it modifies the noun <em>the man.
</em>What man forgot his umbrella? (The one) who bought the coat.<em>
</em>
First person point of view is mostly talking about yourself, meanwhile in a story there will be a lot of I's. Like, "I love the game." "I like candy." First person point of view is yourself.
