jllatimer,
Box X is not an option on the 8949 form. The IRS states:
"If you received a Form 1099-B (or substitute statement) for a transaction, box 2 may help you determine whether your gain (or loss) is short term or long term or subject to special rules. If box 2 is blank and code X is in the "Applicable checkbox on Form 8949" box near the top of Form 1099-B, your broker doesn't know whether your gain (or loss) is short term or long term. Use your own records to determine whether your gain (or loss) is short term or long term."
You need to select B (short term, proceeds reported, basis not reported) or E (long term, proceeds reported, basis not reported) using your own records.
