If you were married as of
December 31st, you must
file as married filing jointly (MFJ) or
married filing separately (MFS).
Married filing jointly almost always results in the lowest tax. The
only way to know for sure is try out MFJ and MFS in TurboTax.
For more information, see
the FAQ below:
https://ttlc.intuit.com/replies/3288477