Are we in the middle of the universe?

"Yet, there is no center to the expansion; it is the same everywhere. The big Bang should be visualized as an ordinary explosion. The universe is not expanding out from a center into space; rather, the whole universe is expanding and it is doing so equally at all places, as far as we can tell"
I know you might be thinking, "How will a Middle Schooler answer me?!"...  I am really a Middle schooler, but my brother in college gave me this answer to your question.

Hope this helps you out!

Answer (d) the universe had cooled enough for atoms to combine, protons and neutrons were too far apart to form nuclei;