Which of the following is a function of the Post Registration Division?

The Post Registration Division is specifically tasked with managing matters related to existing trademark registrations, which includes providing information to trademark owners about their registrations. This can encompass details regarding the status of a trademark, renewal procedures, and any necessary responses to office actions.

The emphasis on providing insightful information about a trademark registration makes this function vital for trademark owners who must navigate the complexities of maintaining and enforcing their registrations. Such support helps ensure that owners are well-informed about their rights and obligations, which is essential for protecting their intellectual property.

In contrast, the other options describe functions that do not fall under the purview of the Post Registration Division. Handling patent inquiries pertains to patent affairs, which is distinctly separate from trademark functions. Filing letters of protest relates to the Trademark Examination process concerning new applications rather than post-registration matters. Coordinating international applications involves aspects of trademark law that cross national boundaries, typically managed by Trademark Operations or other divisions in the USPTO focused on international relations and treaties.