Just use your best judgment. For most nominations on trails, I mark the social section “I don’t know” and exercise and exploration as 
FYI this clarification was made about how to reject nominations in this new review flow;
So it appears that even marking all three as 
is not a rejection. But that has not been stated anywhere.
We can’t just mark something as not meeting criteria, but we can say that it is not “Distinct” in its environment, which I use often for things like lamp posts which are generic infrastructure and should not have been submitted.
It looks like something I would accept, too.