The correct option is C Papilionaceae
The androecium is stamens in the flower which forms a whorl surrounding the gynoecium and is inside the perianth. Stamens can be present as free or fused. The fused stamen can be connate, joined in the same whorl or adnate, joined from more than one whorl. When connate stamens are joined partially into two androecial structures, the condition is termed as diadelphous.
Papilionaceae family is characterized by nine stamen filaments united into a sheath that surrounds the pistil and one separate stamen filament, a condition referred to as diadelphous.
Therefore, the correct answer is option D.