After extensive negotiations, Tune Corporation, a radio manufacturer, and Bill's Comex, Inc., a retailer, entered into a final written agreement in which Tune agreed to sell and Bill's agreed to buy all of its requirements of radios, estimated at 20 units per month, during the period January 1, 1988, through December 31, 1990, at a price of $50 per unit. A dispute arose in late December 1990, when Bill's returned 25 undefective radios to Tune for full credit after Tune had refused to extend the contract for a second three-year period. In an action by Tune against Bill's for damages due to return of the 25 radios, Tune introduces the written agreement, which expressly permitted the buyer to return defective radios for credit but was silent as to return of undefective radios for credit. Bill's seeks to introduce evidence that during the three years of the agreement it had returned, for various reasons, 125 undefective radios, for which Tune had granted full credit. Tune objects to the admissibility of this evidence. "The trial court will probably rule that the evidence proffered by Bill's is
inadmissible, because the evidence is barred by the parol evidence rule.  inadmissible, because the express terms of the agreement control when those terms are inconsistent with the course of performance.  admissible, because the evidence supports an agreement that is not within the relevant statute of frauds  admissible, because course-of-performance evidence, when available, is considered the best indication of what the parties intended the writing to mean.