Concept:Satin stitches are closely worked, flat stitches that can decorate and finish a hem edge neatly when lace is unavailable.
Explanation:• French knots, lazy daisy stitches, and chain stitches are mainly used for decorative details like flower centres, petals, or outlines.
• A hem needs a firm, neat, decorative edge, and satin stitches can cover the hem line and make it look finished without lace.
• Therefore, satin stitches are the most suitable choice for Mary.
Answer:B. satin stitches.