(1) If performance is to be specified by one of the contracting parties, then in case of doubt it is to be assumed that the specification is to be made at the reasonably exercised discretion of the party making it.
(2) The specification is made by declaration to the other party.
(3) Where the specification is to be made at the reasonably exercised discretion of a party, the specification made is binding on the other party only if it is equitable. If it is not equitable, then the specification is made by judicial decision; the same applies if the specification is delayed.