Step 1: Understanding the Concept:
Traditional Indian embroideries feature regional diagnostic stitches to produce unique surface textures.
Step 2: Detailed Explanation:
In the traditional white-on-white Chikankari embroidery of Lucknow, Uttar Pradesh:
Bakhia (Shadow Work) is executed on the reverse (wrong) side of fine, sheer transparent fabrics (muslin, organza, georgette) using close herringbone stitch.
On the right (face) side of the fabric, the crisscrossing threads on the reverse create an opaque, delicate shadow outline effect, while tiny backstitches outline the design motifs.
Step 3: Final Answer:
Thus, 'bakhia' or shadow work refers to the Herringbone stitch, corresponding to option (A).