The Pollen of Seed-Bearing Plants and the Spores of Seedless

The pollen of seed-bearing plants and the spores of seedless vascular plants are both transported by air. How do these structures differ?

A) Spores are diploid individuals, whereas pollen grains are haploid.
B) Pollen contains a mature male gametophyte.
C) Spores are produced by the sporophyte stage of the life cycle, whereas pollen is produced by the female gametophyte stage of the life cycle.
D) Spores are unicellular, whereas pollen grains are multicellular.