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
Gingival massage increases blood supply in: 
Select and explain. 
A. Epidermis, B. Basal layer, C. Lamina propria, D. All of the above
C: Lamina propria
Answer: C: Lamina propria 
Explanation: None