Form 1099-R from OPM

I receive a Form 1099-R from the Office of Personnel Management. This year, as in all years since I began receiving a pension in 2006, OPM has figured out the taxable amount of my annuity for me and has shown that figure in Box 2A. It does not indicate how that figure was calculated. TurboTax asks me if I get periodic payments; yes, I do. It then asks if I started getting those payments in 2025; no, I didn't. The next question is whether, for all the years I've received this form, was the total amount shown (which I assume means Box 1) the amount I paid tax on; no, it wasn't. It then asks whether I used the Simplified Method or the General Rule to figure the taxable amount; neither, as OPM figured the amount in Box 2A for me. Turbo Tax doesn't offer that as a choice, and the On Demand Tax Guidance comes up blank when I click it. I can't answer the question truthfully as Turbo Tax give me only the two options I've cited. Is this a software error that needs to be fixed? If not, how do i properly complete the questionnaire when I'm not offered the correct answer as a choice?