Query Google Spreadsheets, How to display only unique ones?

Question

Google Sheets

Good afternoon, please tell me, there is a query formula:
=UNIQUE( QUERY(A1:C4;"Select A, B, C"))

I use UNIQUE to exclude duplicates, but how to check for duplicates by column "C"
Table:
https://docs.google.com/spreadsheets/d/1dHEBc1UNUF...

Answer 1

In cell D2, enter the formula:
Expand it to the entire column D - unique values ​​and duplicates will be marked in it.
Now you can change the main formula to:

=UNIQUE(QUERY(FILTER(A1:D4;D1:D4="Unique");"Select Col1, Col2, Col3"))

Answer 2

through the filter