Identify the incorrectly matched pair.

Options

A. `{:("Pair of skeletal parts","Category"),("Sternum and ribs","Axial skeleton"):}`
B. `{:("Pair of skeletal parts","Category"),("Clavicle and glenoid cavity","Pelvic girdlw"):}`
C. `{:("Pair of skeletal parts","Category"),("Humerus and ulna","Appendicular skeleton"):}`
D. `{:("Pair of skeletal parts","Category"),("Malleus and stapes","Ear ossicles"):}`

Explanation

To solve the question of identifying the incorrectly matched pair, we will analyze each option provided in the context of the skeletal system.

### Step-by-Step Solution:

1. **Understand the Types of Skeletons**:
- The human skeleton is divided into two main categories: the axial skeleton and the appendicular skeleton.
- The axial skeleton includes the skull, vertebral column, and rib cage, while the appendicular skeleton consists of the limbs and girdles (pectoral and pelvic).

2. **Evaluate the First Pair: Sternum and Ribs**:
- The sternum and ribs are part of the axial skeleton.
- This pair is correctly matched as both belong to the axial skeleton.

3. **Evaluate the Second Pair: Clavicle and Glenoid Cavity**:
- The clavicle is part of the pectoral girdle, which supports the shoulder joint, and the glenoid cavity is the socket in the scapula that receives the head of the humerus.
- This pair is incorrectly matched because the glenoid cavity is not part of the pelvic girdle; it is part of the pectoral girdle.

4. **Evaluate the Third Pair: Humerus and Ulna**:
- Both the humerus and ulna are bones of the upper limb and are part of the appendicular skeleton.
- This pair is correctly matched.

5. **Evaluate the Fourth Pair: Malleus and Stapes**:
- The malleus and stapes are both ossicles in the ear, which are involved in the hearing process.
- This pair is correctly matched as they are both ear bones.

6. **Conclusion**:
- The incorrectly matched pair is the second pair: Clavicle and Glenoid Cavity, as they are part of the pectoral girdle, not the pelvic girdle.

### Final Answer:
The incorrectly matched pair is **Clavicle and Glenoid Cavity**.