Final answer:
The Serratus Anterior is responsible for protraction of the scapula, which is part of the abduction movement of the shoulder blade, not adduction, retraction, or flexion. Other muscles like the erector spinae provide postural support.
Step-by-step explanation:
The action of the Serratus Anterior muscle is not adduction, retraction, or flexion. The primary function of the Serratus Anterior is to facilitate the protraction of the scapula, which means moving the shoulder blade forward and around the rib cage, as when pushing against something or throwing a ball.
The Serratus Anterior also assists in the upward rotation of the scapula, which allows for the arm to be raised above the head, making the correct answer to the student's question 'c. Abduction'. When considering other muscles, the erector spinae provides postural support and assists with extending the vertebral column, while the external intercostal muscles expand the rib cage during inhalation.