Concept: This question tests your knowledge of placentation, which is the arrangement of ovules within the ovary of a flower.

Why (D) is correct: In axile placentation, the ovules are borne on a central axis in a multilocular ovary. The carpels fuse to form septa (partitions) that divide the ovary into chambers (locules), and the ovules are attached to the central placenta. This type of placentation is characteristic of plants like lemon (Citrus), tomato, China rose, and lily.

Why other options are wrong:

• (A) pea: Pea exhibits marginal placentation, where the placenta forms a ridge along the ventral suture of a unilocular ovary, and the ovules are borne on this ridge.
• (B) Argemone: Argemone shows parietal placentation, where the ovules develop on the inner wall of the ovary or on peripheral part. The ovary is unilocular but becomes two-chambered due to the formation of a false septum.
• (C) Dianthus: Dianthus (and Primrose) exhibits free central placentation, where the ovules are borne on a central axis, but the ovary is unilocular and the septa are absent.

NEET Tip: Remember examples for each type of placentation. A good way to remember axile placentation is 'TLC' - Tomato, Lemon, China rose.

Correct Answer: (D)