#1 is obviously different from the other two and correct in its own right. This type of slurring is common in string parts because it allows the high G to be played with a different bowing.

#2 & #3 sound the same. I'm not going to say either is wrong or right, because musicians would play them the same. I will say that the publisher I work for uses #3 as their house style. This type of slurring is common in wind instruments because it allows them to play the high G without having to re-attack it. (which is easier for younger players)

If you want the high G attacked on its own, go with #1. Beyond that, I agree with Jeffrey, and would go with #3. The Barbershop Harmony Society notation manual calls for a slurred phrase to include tied notes.

Jeffrey, Mike, thank you for your comments. Because the notation is for a flute, I think I will stay with #3.