Final answer:
The pectoral girdle, known as the shoulder girdle, includes paired clavicles and scapulas that attach the arms to the trunk.
Step-by-step explanation:
The pectoral girdle is also known as the shoulder girdle. The correct answer to the student's question is 'd. pectoral'. The pectoral girdle, consisting of the paired clavicles (collar bones) and scapulas (shoulder blades), serves to attach the upper limbs to the trunk of the body, specifically to the sternum of the axial skeleton. This enables the shoulders to have a broad range of motion and provides the points of attachment for the upper limbs.