Conditional Format: Highlight an Entire Column if value exists in another cell

I want to highlight an entire column using conditional formatting.

If the text in Column A is contained within Column C, highlight that cell in column C. Otherwise leave that cell non-highlighted. I would like to apply this logic to an entire column.

I have tried to select the range for the entire column within conditional formatting, but it came up with an error.

Any insight on this particular issue would be great appreciated.