Right now the broncos are #1 defense in the league. They have been a great fantasy option this year. But they face their first test this weekend. You could grab them and "wait and see" what happens there.
That imo would be the best move. 49ers and bengals have a easy game this weekend. But they are still a middle of the road squad.
I was basically looking at the exact same list in my league and I went with Cinci. I think they may actually be for real this year/again. Broncos are off to an awesome start but with a cakewalk sched. Not only has Cinci been solid already but a great matchup this week.