The correct option is C meiocyte
Meiocyte is any diploid cell that undergoes meiotic division to form haploid cells or gametes.
Gemmule and conidia are formed by mitosis for asexual reproduction.
Megaspore is formed by the meiotic division of megasopre mother cell. Meiosis does not take place in megaspore. Megaspore undergoes mitotic division to form the embryo sac.