The correct option is C zoospores
Zoospores are asexual spores of algae. They are flagellated (motile) and on germination gives rise to new plants.
Some green algae produce nonmotile spores called aplanospores.
An oospore is a thick-walled sexual spore that develops from a fertilized oosphere in some algae, fungi, and Oomycetes.
A zygospore is a diploid reproductive stage in the life cycle of many fungi and algae. Zygospores are created by the nuclear fusion of haploid cells.