What is the purpose of under stitching in garment construction?

Understitching serves the essential purpose of ensuring that the facing or bottom layer of fabric is kept rolled out of sight, making the garment look cleaner and more polished. This technique involves sewing the facing to the seam allowance, which prevents the facing from showing on the outside of the garment when it is worn. By securing the facing in this manner, it helps to maintain the garment’s shape and appearance, enhancing overall aesthetics.

The other options do not accurately describe the primary function of understitching. While decorative details and texture can be achieved through other sewing techniques, they are not relevant to understitching's specific role. Additionally, providing structural support is generally associated with interfacing or other construction methods, rather than just the understitching process. Therefore, option B is the correct choice as it directly addresses the primary goal of this technique in garment construction.