Turbo Tax is requiring me to select 32a (all investment is at risk) or 32b (some investment is not at risk) on Schedule C. Which one should be selected?

If you don’t know what it means then you should select 32a All at Risk.  It means you are using your own money in the business.

Found this FAQ

https://ttlc.intuit.com/replies/5205776

I found a good post of mine from 3 years ago.

If you don't know what it means then probably All your Investment is at Risk (check Box 32a). It means you are using your own money for the business.

Check Box 32b Not at Risk, if you have amounts invested in this business for which you are not at risk, such as the following:
---Non-recourse loans used to finance the business
---Cash, property or borrowed amounts used in the business that are protected against loss by a guarantee, stop-loss agreement, or other similar arrangement (excluding casualty insurance and insurance against tort liability).
---Amounts borrowed for use in the business from a person who has an interest in the business, other than as a creditor.

If you have money not at risk you can not take a loss on schedule C.