The correct option is A Vexillary
The mode of arrangement of sepals or petals in a floral bud with respect to the other member of the same whorl is called aestivation. In Pisum, vexillary type of aestivation is found. In vexillary type of aestivation, the largest petal (standard) overlaps the two smaller lateral petals (wings) which in turn overlap the two smallest anterior petals (keel). It is also found in bean flower.