In diagram the scutellum is represented by:

The correct answer is Option (3) → Z

The scutellum is the single cotyledon of the grass embryo. It lies on one side of the embryonal axis, pressed against the endosperm. In the figure it is Z.

Option (3) Z — Correct. The scutellum is the single cotyledon of the grass embryo, situated towards one side of the embryonal axis. In the figure, it is Z.

NCERT Extract:
Embryo – “… Embryos of monocotyledons (Figure 1.14 b) possess only one cotyledon. In the grass family the cotyledon is called scutellum that is situated towards one side (lateral) of the embryonal axis. At its lower end, the embryonal axis has the radical and root cap enclosed in an undifferentiated sheath called coleorrhiza. The portion of the embryonal axis above the level of attachment of scutellum is the epicotyl. Epicotyl has a shoot apex and a few leaf primordia enclosed in a hollow foliar structure, the coleoptile.”