**Core Concept**
The adolescent boy's presentation of endocrinopathy, fibrous dysplasia of bone, and hyperpigmentation is suggestive of a rare genetic disorder that affects multiple organ systems. This condition is characterized by the presence of benign growths in the bone, skin, and endocrine system.

**Why the Correct Answer is Right**
The correct diagnosis is McCune-Albright syndrome (MAS), a rare condition caused by activating mutations in the Gs-alpha gene (GNAS1). This mutation leads to the overproduction of cyclic adenosine monophosphate (cAMP), resulting in the characteristic features of MAS. The endocrinopathy is often caused by gonadotropin-independent hypersecretion of sex hormones, leading to precocious puberty. Fibrous dysplasia of bone is caused by the replacement of normal bone tissue with fibrous tissue, leading to bone deformities. Hyperpigmentation is caused by the increased production of melanin due to the stimulating effect of cAMP on melanocytes.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not match the clinical presentation of MAS. The patient's symptoms do not align with the typical features of this condition.
* **Option B:** This option is incorrect because it refers to a different genetic disorder that affects the bone and skin, but does not involve endocrinopathy.
* **Option C:** This option is incorrect because it refers to a different condition that affects the bone and skin, but does not involve the characteristic features of MAS.

**Clinical Pearl / High-Yield Fact**
McCune-Albright syndrome is a rare genetic disorder that affects multiple organ systems, and its diagnosis is based on the presence of characteristic clinical features, including fibrous dysplasia of bone, endocrinopathy, and hyperpigmentation.

**Correct Answer:** C. McCune-Albright syndrome.