Final answer:
The teres minor is one of the four muscles of the rotator cuff within the shoulder girdle.
Step-by-step explanation:
The teres minor is one of the four muscles that make up the rotator cuff, which is a key anatomical feature of the shoulder girdle. The other three muscles of the rotator cuff include the supraspinatus, infraspinatus, and subscapularis. These muscles and their tendons provide stability to the shoulder by fitting like a cuff around the head of the humerus, helping to support and move the joint. Therefore, the correct answer is b) Shoulder girdle.