Article 137
1. Member States may allow taxable persons a right of option for taxation in respect of the following transactions: (a) the financial transactions referred to in points (b) to (g) of Article 135(1); (b) the supply of a building or of parts thereof, and of the land on which the building stands, other than the supply referred to in point (a) of Article 12(1); (c) the supply of land which has not been built on other than the supply of building land referred to in point (b) of Article 12(1); (d) the leasing or letting of immovable property. 2. Member States shall lay down the detailed rules governing exercise of the option under paragraph 1. Member States may restrict the scope of that right of option.