Ovules are borne on

Consider the following statements regarding gymnosperms and choose the correct option.
$I.$ In gymnosperms,the male and female gametophytes have an independent existence.
$II.$ The multicellular female gametophyte is retained within the megasporangium.
$III.$ The gymnosperms are heterosporous.
Of these statements:

Which of the following is the tallest tree in the world?

The microsporophylls of $Pinus$ have:

$A$. Heterospory
$B$. Seed formation
$C$. Fertilization process
Which of the following is appropriate for gymnosperms?

Identify the part labeled as '$A$' in the given figure.