A Reasonable Hypothesis for the Evolution in Pines of a Delay

A reasonable hypothesis for the evolution in pines of a delay in complete development of the female gametophyte until after pollination is that:

A) complete development of the female gametophyte requires fusion of gametes.
B) many seeds fail to be successfully dispersed, and thus investing resources to complete the development of female gametophytes before pollination would be costly.
C) in fact, development of the female gametophyte is continuous, without any pause.
D) many ovules fail to be successfully pollinated, and thus investing resources to complete the development of female gametophytes before pollination would be costly.