Which one is the female gametophyte in angiosperms?

In an embryo sac of a typical angiosperm,there are:

What is present inside the ovarian cavity?

Describe the structure of Megasporangium (ovule) with a diagram.

The embryo sac is represented by:

In angiosperms,the following events occur during megasporogenesis and megagametogenesis:
$(i)$ Differentiation of megaspore mother cells
$(ii)$ Meiosis of the megaspore mother cell
$(iii)$ Formation of a linear tetrad
$(iv)$ Mitotic division of the functional megaspore
$(v)$ Degeneration of $3$ megaspores
$(vi)$ Formation of embryo sac
$(vii)$ Fusion of polar nuclei
The correct sequence is: