Which lens for studio portraits

In a studio situation where I will be shooting at or near F8, saying that space is not an issue, which lens in my signature would you use for portraits that are head/shoulder shots or above the waste shots?

I would go for the 70-200.

70-200.

Coming from 35mm cameras, I'd shoot above the waist shots with the 24-70 between 50 and 70mm...but my preference has to do with how close I used to shoot with 85 and 105mm lenses on the 35mm bod...
Another connsideration is the 85 which will allow you to shoot at wider apertures for less depth of field if that is an objective....

I would use the 70-200, at the highest focal length I can use in the space I have. So if I had enough room for 200mm, I would use 200mm.

70-200