How must the defense of lack of personal jurisdiction be preserved?

The defense of lack of personal jurisdiction must be preserved by raising it in a Rule 12(b) motion or within the initial responsive pleading, such as an answer. This requirement stems from procedural rules that aim to ensure that defendants bring all available defenses and objections to the court's attention early in the litigation process. If the defense is not asserted in the proper manner, it may be waived.

In the context of Rule 12(b) of the Federal Rules of Civil Procedure, this allows a party to move for dismissal based on various defenses, including lack of personal jurisdiction. Including the defense in the answer ensures that it is formally acknowledged and can be addressed by the court, preserving the right to contest jurisdiction.

The other options do not correctly reflect the procedural requirements established in civil procedure. For example, filing immediately after service, while appearing tactically sound, does not capture the specific procedural mechanisms of a Rule 12(b) motion. Including the issue in an arbitration clause is irrelevant to personal jurisdiction over the parties in a court setting. Waiting until the trial begins is improper as it goes against the principle of timely raising objections, which could lead to a waiver of the defense.