Final answer:
The diaphysis of a long bone contains a ring of compact bone that surrounds a central channel filled with bone marrow, which can be specifically identified as yellow marrow.
Step-by-step explanation:
The diaphysis of a long bone is composed of B) a ring of compact bone around a marrow-filled central channel. The diaphysis is the tubular shaft that runs between the proximal and distal ends of the bone. The walls of the diaphysis are made up of dense and hard compact bone, while the hollow region inside, known as the medullary cavity, is filled with yellow marrow. This structure is essential in providing strength and support to the bone, as well as housing the bone marrow, which is important for producing blood cells.