Final answer:
(C) Cambium. The layer of new wood on a tree just under the bark is called cambium.
Step-by-step explanation:
The layer of new wood on a tree just under the bark is called cambium. Cambium is a meristem tissue found in between the xylem and phloem of a tree. It is responsible for the growth of new xylem cells towards the inside and new phloem cells towards the outside of the tree.