Pick out the wrong statement

• A. For a pressure vessel to be classified as thin vessel, the ratio of wall thickness to mean radius is less than 0.1
• B. For calculating forces and efficiency of riveted joint, either rivet diameter or rivet hole diameter is used in case of pressure vessel and in structural work
• C. Longitudinal joint is normally made butt joint to maintain the circularity of the vessel
• D. Maximum diameter of the opening provided in a pressure vessel, which does not require any compensation is 200 mm