Sorry, I wouldn't pick any of your choices.
I would have to go with 7Up just because of the sweetener they use, presumably it is less harmful to our bodies.
I drank diet coke for over 15 years day and night. I can't prove that it is related to the heart condition I now have, but when I quit (about a year ago) my body went into caffeine withdrawals and I developed a heart arrhythmia (no prior history of heart problems) at oddly the same time.
People can argue the possible relation or not, but I believe drinking diet coke for so long did me harm (my own foolish fault) and now I wish I could take it all back.
Anyway, sorry for getting up on a soap box and getting off track, but I hope if anyone should read this perhaps they will consider the potential ill effects of drinking sodas, period.
Blessings and take care...