It just so happens that it's always the same y for each x, but it is only that one y. So this is a function; it's just an extremely boring function! ... So this is a relation, but it is not a function.
Answer: B
Trust me I took the test right now
Anything that has an equla sign would be considered a function.
In this case i would say that everything that has P is equal to would be function, and everything that has a percant sign would be weekly growth rate.
Hope that helps!!!