Answer:
The federal rule must apply in this case.
Step-by-step explanation:
A federal court must, in fact, apply to state law when it has a case that was initiated under state law. However, when this case is also based on diversity of citizenship, a federal statute, or a federal rule, as shown in the case above, the court must apply the federal rule, provided that procedural rule does not interfere or deny any right, as shown in the case of the question above. Therefore, the court must apply federal rule.