This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Growth of the maxilla in the vertical direction is due to: 
Select and explain. 
A. Growth of the alveolus, B. Growth at sutures, C. Growth of the cranial base, D. Growth of the synchondrosis
A: Growth of the alveolus
Answer: A: Growth of the alveolus 
Explanation: None