Final answer:
The appendicular skeleton consists of the bones of the limbs and the girdles that attach them to the axial skeleton, with the femur being a part of it.
Step-by-step explanation:
The appendicular skeleton includes all the bones of the upper and lower limbs, as well as those that connect the limbs to the axial skeleton. This includes bones such as the femur, which is the thigh bone and the longest bone in the human body. Therefore, among the given options, b. Femur is included in the appendicular skeleton.
For clarification, the axial skeleton consists of the skull, vertebral column, and thoracic cage, including the ribs and sternum, which forms the central axis of the body. Hence, the skull, sternum, and vertebrae are part of the axial skeleton, not the appendicular skeleton.