Under what condition may process be served at any place in the United States or outside of it?

The ability to serve process anywhere in the United States or even outside of it is generally governed by specific legal provisions that allow for more flexible service in certain situations. The correct answer highlights that such a condition exists when a multiparty, multiforum action is pending.

In multiparty, multiforum actions, which often involve multiple parties from different jurisdictions, the rules can allow for broader service of process to ensure that all defendants are adequately notified and able to respond, regardless of their geographic location. This facilitates judicial efficiency and fairness in circumstances where the resources and attention of the court may need to be applied across state or national borders due to the complex nature of these cases.

In contrast, the other options typically do not provide the same broad basis for service of process across jurisdictions. For instance, class action lawsuits usually have their own specific rules about service that may not include the latitude afforded under multiparty scenarios, and state law claims or criminal cases have more defined jurisdictions and limitations on where defendants must be served. Thus, the unique framework of multiparty, multiforum actions justifies the broader latitude for process serving.