The part which provides nourishment to the developing embryo is:

The correct answer is Option (2) → Y

Y is the large starchy tissue filling most of the grain: the endosperm. Maize is an endospermic (albuminous) seed, so this food store remains in the mature seed and feeds the embryo when it germinates.

Option (1) A — Incorrect. A is the coleoptile, the sheath over the shoot tip.

Option (2) Y — Correct. The endosperm stores reserve food and nourishes the developing embryo. In the figure, the endosperm is Y.

Option (3) B — Incorrect. B points to the shoot apex and leaf primordia inside the coleoptile.

Option (4) D — Incorrect. D is the coleorhiza, the sheath round the radicle.