The right answer is haploid spores that will undergo mitosis.
The reproductive cycle of pteridophytes, for example, consists of the alternation of a diploid phase and a haploid phase. On the leaves of the ferns (diploids) there appear sporangia in which meiosis producing haploid spores occur, which are scattered by the wind. Germination gives rise to a small mass of haploid cells, the prothallus. This prothallus (representing the gametophyte haploid) will produce male and female gametes that will meet: fertilization. The egg cell resulting from this encounter develops and gives back a new diploid organism, on whose leaves sporangia appear .....