**Core Concept**
The appearance of ossification centers in bones is a crucial aspect of skeletal development. Ossification centers are the sites where bone formation begins, and their appearance and development are essential for understanding bone growth and maturation.

**Why the Correct Answer is Right**
The appearance of ossification centers in bones is a complex process that involves the transformation of cartilage into bone tissue. In the case of the bones that appear just before birth, the ossification centers typically appear between 28 and 38 weeks of gestation. The correct answer is the bone that has an ossification center that appears just before birth. The ossification center of the clavicle (collarbone) appears in the 14th to 16th week of gestation, but the ossification center of the pubic bone appears at around 36 to 38 weeks of gestation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the ossification center of the scapula (shoulder blade) appears in the 4th to 6th week of gestation, which is much earlier than just before birth.
**Option B:** This option is incorrect because the ossification center of the humerus (upper arm bone) appears in the 6th to 8th week of gestation, which is also much earlier than just before birth.
**Option C:** This option is incorrect because the ossification center of the femur (thigh bone) appears in the 8th to 12th week of gestation, which is even earlier than the options above.

**Clinical Pearl / High-Yield Fact**
The appearance of ossification centers in bones is an essential aspect of skeletal development, and understanding their timing and sequence is crucial for diagnosing skeletal anomalies and disorders.

**Correct Answer: D. Pubis**