Answer:
C is correct because angiosperms are the only organisms in the plant kingdom that create flowers.
Step-by-step explanation:
A is incorrect because gymnosperms (conifers, cycads, ginkgo) also bear seeds.
B is incorrect because the majority of extant plants are vascular plants.
D is incorrect because the gametophyte in angiosperms is significantly reduced in size compared to that of gymnosperms.