Pick out the wrong statement.

• Rivetting provides a permanent fastening method.
• The joint made by overlapping of one plate over the other, and then rivetting the two plates together with two rows of rivets is called 'double rivetted butt joint'.
• Shank diameter of the rivets should be less than the size of the hole drilled in the plate for rivetting.
• The efficiency of a rivetted joint is the ratio of the strength of the rivetted joint to the strength of the solid plate.