Solution

Gymnosperms are the naked seed-bearing plants. A naked seed means that the ovules are not completely enclosed by sporophytic tissue at the time of fertilization.
Most of the seed plants have pollen, which contains and transports the sperm to fertilize the egg.
As pollen is resistant to desiccation, the sperm can be transported between plants across large distances without drying up.
The gymnosperms (naked seed plants) consists of four phyla. These are conifers, cycads, gingkoes, and gnetophytes. Cycads produce pollen, but the sperm still swims down the pollen tube using flagella.
As it also has a naked seed, it is classified as a gymnosperm.
Hence, option C is correct.