IF statement with four columns to choose from

Hello, I have spreadsheet with several columns for 'employee'. Let's call column B the current employee. Columns C, D and E may indicate a new employee taking over next year. What are some strategies for pulling the new employee name, if one exists, into a new column, otherwise pulling the current employee name into that cell, if no new employees exist?

This is easy with two columns, because it's an IF statement with only two choices, but I don't see how to build three or more choices into the formula. An example is attached. Column F is what I'm trying to generate with a formula.

Thank you,

How about

Formula:

=LET(a,TOCOL(C2:E2,1),IF(COUNT(ROWS(a))=0,B2,IF(ROWS(a)>1,"Error",a)))

These both do the trick. I think CountA is one of my blind spots as well as ToCol.

Thank you,

Glad to help & thanks for the feedback.