Aplaintiff is suing a defendant in federal court for personal injuries arising out of an automobile accident. the defendant's automobile insurance policy covers the accident. must the defendant disclose the existence of the insurance policy? a yes, because it is required under the federal rules. b yes, unless the discovery of the insurance coverage would not lead to other discoverable evidence. c no, unless the plaintiff submits an interrogatory. d no, because insurance coverage cannot be mentioned at trial.