What is the best type of scope for a m4 carbine airsoft gun?

I would like to choose inbetween a red/green dot scope(no zoom), a red/green dot scop with small amounts of zoom, and a holographic sight. My money range is about $80. My gun shoots about 400 fps and has a 502mm 6.01 mm barrel inside, making it have a longer range. I also play in field games, not much of a cqb guy.