**Core Concept**
The question requires identifying the superior-most structure visible on a normal X-ray of the shoulder joint. This involves understanding the anatomical layout of the shoulder girdle and its relationship with the surrounding bones and soft tissues.

**Why the Correct Answer is Right**
On a normal X-ray of the shoulder, the coracoid process is usually the most superior structure visible. This is because the coracoid process is a small, hook-like projection located at the top of the scapula (shoulder blade) and is a key landmark for shoulder joint alignment. The coracoid process serves as an attachment point for several muscles and ligaments that stabilize the shoulder joint.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided, so we'll move on.
* **Option B:** The acromion process is a bony projection on the scapula, but it is not the most superior structure on a normal X-ray of the shoulder. The acromion process is actually located below the coracoid process.
* **Option C:** The clavicle (collarbone) is a long, slender bone that extends from the shoulder to the breastbone, but it is not the most superior structure visible on a normal X-ray of the shoulder. The clavicle is located more inferiorly than the coracoid process.

**Clinical Pearl / High-Yield Fact**
When interpreting X-rays of the shoulder, it's essential to identify the coracoid process as the most superior structure. This helps in assessing the alignment and integrity of the shoulder joint, which is crucial for diagnosing and managing various shoulder injuries and disorders.

**Correct Answer: C. Clavicle**