Apply two conditional formatting rules simultaneously

Hi there. I am trying to apply two conditional formatting rules simultaneously but I am not getting the desired results.

The rules are:

Highlight with red if the column B is Empty and if column C is equal to ROSS AND Highlight with red if the column A is Empty and if column C is contains the string "Lois"

And the fomula used in the formatting is:

=OR(AND(ISBLANK*(B1);C1="ROSS");AND(ISBLANK*(A1);AND(COUNTIF(C1;"*Lois*"); "YES";"NO")="YES"))

I am attaching a short Excel file.

Thank you

Thank you, that was the solution. Highly appreciated.