Answer:
C. gametes
Explanation:
The alternation of generations is a process of reproductive cycles that occur in plants, algae and cnidarians. The main characteristic of this type of reproduction is that it happens in two different generations alternating in a single life cycle of the organisms.
For this process to occur in plants, it is necessary that there is a generation that produces spores (sporophytic generation) and a generation that produces gametes (gametophytic generation). The generation that produces spores should produce diploid cells, while the generation that produces gametes must produce haploid cells.
When haploid cells arise from the germination of spores (which are haploid), the phase called gametophytic begins in the body, where the formation of two gametes (one male and one female) occurs. These gametes will merge during fertilization, generating a diploid embryo, which will undergo several mitoses until it becomes an adult that is capable of forming spores.