A triple riveted butt joint with double straps of unequal width is to be designed for a boiler shell. The pitch of the rivets in the outer row is double the pitch in the inner row and zigzag riveting is proposed. Which of the following statement is correct?

A. There are four rivets per pitch length, all in double shear

B. There are four rivets per pitch length, out of which two are in single shear and two are in double shear

C. There are five rivets per pitch length, all in double shear

D. There are five rivets per pitch length, out of which four are in double shear and one is in single shear