Final answer:
The correct answer is 'c. teres major,' as it is not a part of the rotator cuff muscles, which include supraspinatus, infraspinatus, teres minor, and subscapularis.
Step-by-step explanation:
The student's question is about identifying which muscle is not part of the rotator cuff. The rotator cuff is comprised of four muscles: the supraspinatus, infraspinatus, teres minor, and subscapularis, which are responsible for stabilizing the shoulder joint.
The option that is not a part of the rotator cuff is c. teres major. The teres major is often confused with the rotator cuff muscles because it is in close proximity to the teres minor. However, it serves different functions, such as extending, adducting, and medially rotating the arm. Therefore, the correct answer to the question 'All of the following are rotator cuff muscles except' is c. teres major.