Concept:Primary succession on bare rock begins with pioneer organisms that can survive without soil.Explanation:Bare rock has no soil, so the first colonisers must be hardy organisms that can attach to rock and help break it down.Lichens are able to grow on bare rock and secrete acids that weather the rock, starting soil formation.Mosses, ferns, and fungi usually appear later when some soil has already formed.Therefore, the most likely first colonisers of bare rock are lichens.Answer:C. lichen