The correct option is D Large, top-like, spirally twisted with cilia
Male gametes of Cycas are large, top-like, spirally twisted with cilia. In the male strobiles (cones) there are microsporophylls (fertile leaves of the strobile), that contain microsporangia. Within the microsporagium spore mother cells undergo meiosis and generate haploid microspores. The microspore wall develops into winglike projections (to facilitate its aerial propagation) and mitosis occurs producing two cells, the generative cell and the tube cell. The final structure containing these elements is the pollen grain.