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
Changes in the gingiva during pregnancy are attributed to 
Select and explain. 
A. Changes in the hormonal level, B. Altered microorganisms, C. Altered immunological responses level, D. All the above
A: Changes in the hormonal level
Answer: A: Changes in the hormonal level 
Explanation: None