If the obligation of B is to deliver 50 bottles of whisky and pay P10,000.00 cash, or 75 bottles of whisky and P5,000.00 cash, or 25 bottles of whisky and P15,000.00 cash, the transaction shall be considered a barter or sale depending on the manifest intention of the parties. Under Article 1468, if such intention does not clearly appear, the contract shall be considered barter, where the cash involved is P5,000.00, or a sale, in case it is P15,000.00, or either in case it is P10,000.00. explain