Defendant is on trial for extorting $10,000 from Victim. An issue is the identification of the person who made a telephone call to Victim. Victim is prepared to testify that the caller had a distinctive accent like Defendant's, but that he cannot positively identify the voice as Defendant's. Victim recorded the call but has not brought the tape to court, although its existence is known to Defendant. Victim's testimony is 
inadmissible, because Victim cannot sufficiently identify the caller.  inadmissible, because the tape recording of the conversation is the best evidence.  admissible, because Defendant waived the "best evidence" rule by failing to subpoena the tape.  admissible, because Victim's lack of certainty goes to the weight to be given Victim's testimony, not to its admissibility. 