In the case of co-pending applications claiming the same invention, what must an examiner do?

In the context of co-pending applications claiming the same invention, the correct approach for an examiner is to issue a provisional rejection of the later-filed application. This provisional rejection indicates that the later-filed application faces potential problems due to its claims being too similar to those in an earlier application.

The process of issuing a provisional rejection allows the applicant of the later-filed application an opportunity to respond and address the similarities, possibly by amending claims or providing arguments to distinguish their invention from the earlier application. This step is crucial in ensuring that the examination process provides a thorough assessment of the claims and maintains the integrity of the patent system by avoiding the grant of multiple patents for the same invention.

The other choices suggest actions that would not be immediately appropriate. For instance, outright rejection for anticipation under 35 USC 102(a)(1) or 35 USC 102(a)(2) implies a finality that does not take into account the ability for the applicant to amend or argue against the rejection. The mention of a terminal disclaimer relates to resolving double patenting issues, which typically occurs after a final determination of claims similarity and is not the initial step taken by an examiner in processing co-pending applications.