Answer:
The sentence here is:
"mi hermano y yo_________ al supermercado."
Which means something like:
"My brother and i ____ at the supermarket"
This can be completed with "went" or "fuimos" in Spanish.
The conjugation is "fuimos" because the person, in this case, is "nosotros"
So the completed sentence is:
Mi hermano y yo fuimos al supermercado.
