What is the formula to calculate the fold size of the seam in locked groove joint?

A. Fold size = width of the lock - 2 times the material thickness

B. Fold size = width of the lock - 3 times the material thickness

C. Fold size = width of the lock - 4 times the material thickness

D. Fold size = width of the lock - 5 times the material thickness

Correct Answer: Fold size = width of the lock - 5 times the material thickness