3. a. When the Euro first becomes the monetary unit of participating member states of the European Union, references to the ECU in a contract, security or instrument shall be replaced by references to the Euro at the rate of one Euro to one ECU.
b. If is it unclear that a contractual reference to the ECU is a reference to the official definition of the ECU, it shall be presumed to be a reference to the ECU, which presumption shall be rebuttable, taking into account the intentions of the parties.