Synchrony Financial Credit Card Complaint

Synchrony Financial Credit card department,

Payoff process Illinois

I have an Amazon credit card issued by Synchrony Bank. I am trying to understand payment allocation and interest application policies used for this account but online information and customer service were not helpful. The website offers - payment allocation methods. The standard, option 1, applies payment amounts in addition to the minimum payment to interest accruing, non-promotional balances first and then promotional balances ... except in the last two months of an expiring promotion where anything in excess of the minimum gets applied to the expiring promo balance. Option 2 applies the ENTIRE payment, including minimum payment, to non-interest accruing promo balances. Option 3 seems to do the same thing as option 1. My questions are : 1. How is option 1 different than option 3? 2. How is the minimum payment calculated and applied for each allocation method? 3. In a statement period where I have a non-promotional balance AND ALSO an expiring promotion, how do I calculate the payment amount required to pay off the expiring promo balance in full and also the non-promotional balance such that no interest is charged on either. 4. In the above scenario, which payment allocation option would be most suitable if the goal is to not pay any interest?