Populate cell with not previously chosen option among 2 possible options...

I want to populate cells A1 and A2 with the information in column C.

The text of the column C entries will vary, but column C will always contain only two different entries throughout (ex. "ABC" and "XYZ" one time, "ABC" and "DEF" the next, etc.). I would like to have A1 populated with whichever of the two entries shows up first in the column (so, whatever is in C1 (assuming no column labels)... and A2 populated with the other.

The spreadsheet will never know in advance what the specific text of the two entries are. So I assume the only way to do this is by telling A1 to be C1, and then telling A2 to be the first column C cell it finds that isn't equal to C1.

What formula would I use to do this?

Thanks for the help.

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