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: Pathology
Aphthous ulcers are known as - 
Select and explain. 
A. Canker sores, B. Marjolin's ulcer, C. Curling's ulcer, D. Cushing ulcers
A: Canker sores
Answer: A: Canker sores 
Explanation: Aphthous ulcers 

Also known as Canker Sores
These are superficial Ulcerations of the oral mucosa.
The lesions may be Single or multiple.
Ulceration is surrounded by an erythematous halo and is Covered by a thin exudate.