This is a question with answer options. Goal: How to create a simple sheath for a knife?

Which of the following methods is more reasonable for accomplishing this goal?

Possible answers:
A). Take two pieces of leather of differing size, use a box cutter to cut them to size, sew some thread through the center to secure them together;
B). Take two pieces of leather of equal size, use a box cutter to cut them to size, sew some thread through the perimeter to secure them together;...I think the answer is
B).