Final answer:
The connective tissue joining the anterior end of a rib to the sternum is hyaline cartilage, which facilitates the attachment and provides flexibility.
Step-by-step explanation:
The flexible connective tissue that joins the anterior extremity of a rib to the breast bone (sternum) is hyaline cartilage. Ribs are attached to the sternum via their costal cartilage made of hyaline cartilage, which provides the necessary support and flexibility.
This type of cartilage covers the ends of bones where they meet to form joints, is found in the rib cage, and makes up part of the embryonic skeleton before bone formation. Therefore, the correct answer is b) hyaline cartilage.