You need to enter your 1099-R and include the amount in Box 1 on your tax return regardless of the entry in box 2A Taxable amount. Please post the three choices, you referenced in your question, in the comments section so I can help you with your choice. Also, please list any of the boxes that have amounts in them, and what distribution code is in box 7 in the comments section.
Generally, the amount shown in box 2a is the amount of the distribution that is taxable. However, if the payer is unable to reasonably obtain the data necessary to compute the taxable amount, this box may be blank and the Taxable amount not determined box in box 2b will be checked.
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