The proponent may use a copy to prove the span of an official record—or of a document that was recorded or filed in a public office as authorized by law—if these conditions are met: the record or document is otherwise admissible; and the copy is certified as correct in accordance with Rule 902(4) or is testified to be correct by a witness who has compared it with the original. If no such copy can be obtained by reasonable diligence, then the proponent may use other evidence to prove the span.