Concept: This question tests your knowledge of floral morphology, specifically the structure of the ovary and the presence of a false septum in certain plant families.

Why (A) Brassica is correct: In plants belonging to the family Brassicaceae (Cruciferae), such as Brassica (mustard), the ovary is typically unilocular (one-chambered) at the initial stage. However, it becomes bilocular (two-chambered) due to the development of a false septum, known as a replum, which extends from the placenta and divides the ovary cavity.

Why other options are wrong:

(B) Pisum: Pisum sativum (pea) belongs to the family Fabaceae and has a unilocular ovary without a false septum.

(C) Hibiscus: Hibiscus belongs to the family Malvaceae and typically has a multilocular ovary (e.g., 5-chambered) with true septa.

(D) Dianthus: Dianthus (carnation) belongs to the family Caryophyllaceae and has a unilocular ovary with free central placentation, without a false septum.

NEET Tip: Remember that the presence of a replum (false septum) is a characteristic feature of the Brassicaceae family, which helps in identifying members of this family.

Correct Answer: (A)