Answer: A..?
Explanation:
I think A completes the sentence. I am VERY VERY VERY sorry if that answer doesn't work.
A person who arrives with a retinue is arriving with other people.
A retinue is a group of other people who accompany an important person.
Ours is the only yard on our block with a fence.
This possessive pronoun form correctly completes the sentence :D
-- Hope this helps!
