What must a person who serves a summons be authorized under?

The correct answer pertains to the requirement that a person serving a summons must be authorized under Rule 40(d). This rule specifies the qualifications and procedures that must be followed when serving legal documents such as summonses. It ensures that process servers are properly trained and have the necessary legal standing to carry out this important function.

In the context of legal processes, serving a summons is a critical step in ensuring that individuals are informed of legal actions being taken against them, which upholds the principles of due process. Rule 40(d) thus establishes clear guidelines to maintain the integrity of the service process.

The other rules mentioned do not specifically address the qualifications or authorization necessary for serving a summons, which is why they are not applicable in this context. Understanding the specific rules related to the serving of legal documents is essential for anyone involved in the legal process, ensuring that proceedings are conducted fairly and according to established legal standards.