The correct option is A Lichens
A pioneer organism is an organism that populates a region after a natural disaster or any other that may have caused most life in that area to disappear. Common pioneer species include bacteria, fungi, and lichens. So the correct option is lichens. Lichens are survival experts and live in diverse habitats, from frigid zones to the tropics. They can even be found in some of the most inhospitable environments where many other plants can not survive, such as extremely dry deserts where day and night temperatures vary greatly, high mountains that are permanently covered with snow, and frosty tundra in polar areas. Once lichens have been growing on rocks for a while, mosses, green algae, and hornworts are able to survive there too. So these organisms are not pioneer species because they usually appear after the original pioneer species have taken residence.