Concept: This question tests your knowledge of floral formulas, specifically the characteristic floral formula of the Family Fabaceae (subfamily Papilionoideae) and its unique corolla structure.

Why (B) is correct: The Fabaceae family (subfamily Papilionoideae) exhibits a characteristic papilionaceous corolla. This corolla consists of five petals arranged in a specific way: one large posterior petal called the standard (or vexillum), two lateral petals called wings (or alae), and two anterior petals that are fused together to form a boat-shaped structure called the keel (or carina). Therefore, the representation ${\mathrm{C}}_{1+2+(2)}$ correctly denotes one standard petal, two wing petals, and two fused keel petals (indicated by the parenthesis).

Why other options are wrong:

• (A) ${\mathrm{C}}_{1+2+2}$: This implies two separate keel petals, which is incorrect as they are fused.
• (C) ${\mathrm{C}}_{1+2+3}$: This indicates a total of 6 petals, which is not characteristic of Fabaceae.
• (D) ${\mathrm{C}}_5$: This indicates five free petals, which does not represent the papilionaceous corolla with fused keel petals.

NEET Tip: Remember the structure of the papilionaceous corolla: 1 (standard) + 2 (wings) + (2) (fused keel). The parenthesis indicates fusion.

Correct Answer: (B)