Box 7 on my 1099-R says 0, but that's not an option on TurboTax. What should I do next?

If there is a 0 (zero) entered in box 7 of the Form 1099-R, you will have to contact the plan administrator to get a corrected Form 1099-R.  There is no such code 0 for box 7.

Contact your plan administrator.  Box 7 is a distribution code and 0 is not one of the codes that the IRS recognizes. 

What do all the codes in Box 7 of the 1099-R mean?

Look again at the Form 1099-R.  It's doubtful that box 7 actually has a zero in it because no payer would ever have a reason to put a zero in box 7.  Perhaps there is a 7 in box 7.