To show that it is the second such award earned, which of the following devices should be added to the ribbon representing a Navy-Marine Corps achievement medal?

To indicate that a service member has earned a second award of the Navy-Marine Corps Achievement Medal, a gold star device is added to the ribbon. This practice follows the established protocol for military awards where devices are used to signify subsequent awards. In this case, a gold star represents the second award, while a silver star is typically used to denote a higher level of achievement or a subsequent award of a specific medal that has a distinct hierarchy. The bronze star is not applicable here as it signifies different levels of commendation or a separate award entirely. Cluster devices generally refer to a way to denote multiple awards of the same medal but in a different context or with different designs than the star device used here. Using a gold star effectively communicates the recipient's continued excellence and recognizes their repeated contributions within the framework of the Navy-Marine Corps Achievement Medal.