One Reason for the Enormous Evolutionary Success of Seed Plants

One reason for the enormous evolutionary success of seed plants as a group is their possession of

A) complex leaves that can photosynthesize at a faster rate than non-seed-producing plants can.
B) seeds with food reserves for the young gametophyte.
C) seeds with a resting stage that can remain viable for many years, germinating when conditions are favorable for growth of the sporophyte.
D) seeds that are dispersed by wind.
E) mobile pollen.