Please help with QC scorecard I am trying to create

Please see attached spreadsheet and advise. I want the risk ranking(3rd row) to rank based on the percentage(1st raw) of column C, D and E.

If the percentage is 100% - 90% then low

If below 90%-70% then fair

and If Below 70% then High

Please help.

Thanks

Sorry If I was not clear. I want the ranking on each individual column. thanks

anyone? please help