All Pteridophytes have a true alternation of generations, in which a dominant sporophyte generation produces spores through meosis, and a free-living gametophyte generation forms gametes (egg and sperm) by mitosis. The gametophyte produced by the germination of spore is thalloid and is often called as prothallus. It is monoecious i.e., bears both male (antheridia) and female (archegonia) sex organs. Hence the correct option is A.