What is the effect of an amended complaint relating back to the original complaint's filing date?

The correct choice highlights the principle of relation back, which means that if an amended complaint relates back to the original complaint's filing date, it retains the original lawsuit's active status despite any intervening delays. This is particularly important in ensuring that a plaintiff’s case is not dismissed due to procedural delays or the expiration of the statute of limitations on claims that might have been included in the original complaint. When an amended complaint relates back, it allows the original action to continue without interruption, thereby preserving the plaintiff's right to have their claims heard in court.

The other options do not accurately reflect the effect of an amended complaint relating back to the original complaint's filing date. For instance, while an amended complaint can introduce new claims, it is not the primary effect of relation back, which specifically pertains to keeping the lawsuit active and valid in light of the timing issues. The amendment does not extend the court's jurisdiction nor eliminate the need for a new trial, as those concepts are governed by other legal principles and rules.