Answer: A). lichens and low-growing moss
The tundra is characterized by extremely low temperatures as well as little precipitation, a rocky landscape, and permafrost. These physical features does not support a landscape with healthy vegetation. This will be a primitive landscape as it cannot support growth of large trees. Lichens and low-growing moss are organisms which can grow in these rocky permafrost substrates. Lichens will release acids which will make the ice melt and can cause withering of rocks into small particles of soil. The available soil on rock surface can facilitate the growth of small mosses.