I have a List

List[0]: .colA:”Red”. colB:”Big”.colC:”2020″.colD:”info0a”.colE:”info02″.

List[1]: .colA:”Red”. colB:”Big”.colC:”2021″.colD:”info1a”.colE:”info12″.

List[2]: .colA:”Red”. colB:”Big”.colC:”2022″.colD:”info2a”.colE:”info22″.

List[3]: .colA:”Red”. colB:”Small”.colC:”2021″.colD:”info3″.colE:”info32″.

List[4]: .colA:”Red”. colB:”Small”.colC:”1999″.colD:”info4a”.colE:”info42″.

List[5]: .colA:”Blue”. colB:”Small”.colC:”2023″.colD:”info5a”.colE:”info52″.

List[6]: .colA:”Blue”. colB:”Small”.colC:”2025″.colD:”info5a”.colE:”info52″.

I want ,first groupby for colA and colB,then select the oldest record according to colC, so the result should be

colA:”Red”.colB:”Big”.colC:”2020″.colD:”info0a”.colE:”info02″.(for Red,Big,oldest is 2020)

colA:”Red”.colB:”Small”.colC:”1999″.colD:”info4a”.colE:”info42″.(Red,Small,oldest 1999)

colA:”Blue”.colB:”Small”.colC:”2020″.colD:”info5a”.colE:”info52″.(Blue,Small, oldest 2023)

May I know how to do it? Thank you