You are answering a USMLE-style medical question. Question: A 3-year-old male is brought in to his pediatrician by his mother because she is concerned that he is not growing appropriately. Physical examination is notable for frontal bossing and shortened upper and lower extremities. His axial skeleton appears normal. He is at the 7th percentile for height and 95th percentile for head circumference. He demonstrates normal intelligence and is able to speak in three-word sentences. He first sat up without support at twelve months and started walking at 24 months. Genetic analysis reveals an activating mutation in a growth factor receptor. Which of the following physiologic processes is most likely disrupted in this patient’s condition? Options: A) Intramembranous ossification B) Osteoblast maturation C) Endochondral ossification D) Production of type I collagen Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.