Universal Hiring uses Salesforce to capture job applications. A salesforce administrator created two custom objects; Job__c acting as the master object, to Application_c acting as the detail.

Within the Job__c object, a custom multi-select picklist, preferred _Locations__c, contains a list of approved states for the position. Each Job_Application__c record relates to a Contact within the system through a master-detail relationship.

Recruiters have requested the ability to view whether the Contact's Mailing State value matches a value selected on the Preferred Locations__c field, within the Job_Application__c record. Recruiters would like this value to be kept in sync if changes occur to the Contact's Mailing State.

What is the recommended tool a developer should use to meet the business requirement?