Section: Volume J

Section: Volume E

Explanation
To prevent users from selecting more than one value on a picklist field, the administrator needs to change the field type from a multi-select picklist to a regular picklist, and select the "Choose only one value" checkbox on the field definition page. This will ensure that only one value can be selected on the record page and in reports and filters. References: https://help.salesforce.com/s/articleView?id=sf.customize_picklists.htm&type=5