What is the characteristic posterior petal of the Papilionoideae corolla called?

Read the following statements.
$(i)$ Gynoecium is situated in the centre and other parts of the flower are located on the rim of the thalamus almost at the same level.
$(ii)$ Ovary is half-inferior.
$(iii)$ Examples are plum,rose and peach.
Which condition of flowers is being described by the above statements?

Ligulate/strap-shaped corolla occurs in sunflower in

Among Indigofera,Sesbania,Salvia,Allium,Aloe,mustard,groundnut,radish,gram,and turnip,how many plants have stamens of different lengths in their flowers?

Among china rose,mustard,brinjal,potato,guava,cucumber,onion and tulip,how many plants have superior ovary?

Which of the following has a cup-shaped thalamus?