Objective: To measure strips of denim for weaving,

Which of the following solutions is more sound in terms of naive physics reasoning?

Possible answers:
[a]. Lay the denim on a carpeted floor, place a ruler along the edge of the fabric, and use a pen to mark every 1" along the fabric.;
[b]. Lay the denim on a cutting mat, place a ruler along the edge of the fabric, and use a pen to mark every 1" along the fabric.;
[b].