I am creating a spreadsheet where at the end of each row there will be 3
columns: YES/NO/NA. Is there a formula for if one is 'X'ed it will
automatically clear the other two columns if there were 'X'ed previously?

Or how do I correctly write:
IF C2=X, THEN D2 is blank, AND E2 is blank

Is it even possible?

Please help, Thanks!