The correct option is
A Position of gynoecium
A floral formula is a means to represent the structure of a flower using numbers, letters and various symbols, presenting substantial information about the flower in a compact form. It can represent particular species, or can be generalized to characterize higher taxa, usually giving ranges of organ numbers.
Whereas a floral diagram is the depiction of the flower in the vertical section. It shows floral symmetry (actinomorphic or zygomorphic), ebracteate and bracteate nature of the flower, aestivation of calyx and corolla, number of floral cycles, cohesion and adhesion of floral parts, complete and incomplete flower, perfect and imperfect flower.
The floral diagram does not show the position of the gynoecium. It is shown by making bars in the floral formula.
So, the correct answer is option C.