Sorry, but what is your question?
Is it the uniqueness of ranks? This you already implemented with the function "unique()". You'd better give a validation tip, too.
Or is it the "Other. please specify"? Do you want to have a text field right there?
In my opinion better you display a separate question of type short text if the "Other" option is selected on one of the five ranks.
 
Why did you choose an "array by column" in the first question and an "array" in the second question?
For your "array by column" question you should use the function "countif()" to check if the "Other" code was selected.
In your "array" question a simple check whether the "Other" option is not empty is sufficient.

Though this is of course possible, and often shown in the forum.
 
 


How do you want to handle this?
If a respondent clicks something like this without intention?

No chance to remove a click.

Joffm