Basically, I have an excel sheet similar to the below. I want to use the YES cells to create an equation for the source column which indicates the source of the yeses.

| Header 1 | Header 2 | Header 3 | Source |
| --- | --- | --- | --- |
| YES | NO | NO | Header 1 |
| NO | YES | NO | Header 2 |
| NO | YES | YES | Header 2 and Header 3 |