What is required for a defendant to validly make a crossclaim against another defendant?

The correct answer emphasizes the fundamental principle of crossclaims, which is that they must arise from the same transaction or occurrence as the original claim or the other party's claim. This requirement ensures that the claims are related and that the court can adjudicate them efficiently within the same proceeding.

By keeping all related disputes in one case, the judicial system aims to avoid multiple lawsuits regarding the same events, to promote judicial economy, and to deliver a comprehensive resolution of the issues at hand. The focus on the transactional link helps the court address all interconnected claims and defenses at once, benefiting both the parties involved and the efficiency of the court.

In contrast, the other answer choices do not align with established legal principles surrounding crossclaims. For instance, requiring an equal number of counterclaims or agreement between defendants unnecessarily complicates the process and does not reflect the rules governing civil procedure. Similarly, mandating new evidence is not a prerequisite for a crossclaim; it is focused on claims that relate to the existing legal issues and facts, rather than the introduction of new evidence. This clarity around the transaction or occurrence requirement helps ensure that the crossclaims operate within the correct procedural framework.