Answer:
a. êtes
Explanation:
Firstly, we need the correct verb that conjugates with "vous". This eliminates both avons and est. That leaves us with just "êtes" or "avez", which is quite tricky to differentiate which one to use. Thankfully, there is a special yet quite odd way to remember what verbs conjugate with etre. This pneumonic device is called "Dr. Mrs. P Vandertramp" if you're interested, but all you need to know is that rentrer is one of those words. Therefore, "êtes" is the correct verb missing from the sentence.
