Cycas is classified as a gymnosperm due to its motile sperms, fruit formation, naked ovule, and phycnoxylic wood.

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) consist 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.