Conditional column not selecting nulls

[ZachUnger]

Hi Team 

I'm trying to create the below conditional column but it is giving me the below error. 

"[Expression.Error] We cannot convert the value null to type Logical."

Does anyone know how I can get around this to show all blanks/null as CAO's? 

Thanks 

Zach 

[Ahmedx · Accepted solution]

you need to first compare to null and then to the rest