Of the three, the red, nothing is faster than nothing there at all

If the wing can be tapered to almost nothing and then flat on the end is even better. I fly Jets exclusively and all the fast ones taper down and are either rounded or squared off. But when you taper, you can afford to have aesthetically pleasing rounding of the wing tip.

Edit: in hindsight, because number two is heavily tapered or thinner than number three, it is faster. But I assumed we were talking shape, and not the actual wing.