Under which rule can amendments to the original filing be made?

The correct answer pertains to Rule 15, which specifically addresses amendments to pleadings and other documents in civil cases. This rule allows parties to amend their original filing to correct errors, clarify claims or defenses, or to add new information that may be relevant to the case.

Rule 15 is significant because it provides a structured process for modifications, ensuring that amendments can be made without unjustly disadvantaging the other parties involved. It typically allows amendments as a matter of course under certain circumstances, such as within a specified time frame after the original document was filed, promoting fairness and justice in the legal process.

In contrast, the other rules mentioned do not primarily focus on the amendment process. Rule 7.1 deals with the requirements for filing motions and supporting documents, Rule 12 outlines defenses and objections in response to pleadings, and Rule 18 pertains to joinder of claims. Consequently, these rules do not provide the framework necessary for making amendments to original filings, which is why they are not applicable in this context.