This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Human Immunodeficiency Virus, Subject name: Microbiology
In a patient having HIV infections, oral ulcer is most commonly due to: 
Select and explain. 
A. Candida, B. Cryptococcosis, C. Histoplasma, D. Trichophyton
A: Candida
Answer: A: Candida 
Explanation: Ans. is 'a' i.e., Candida (Ref: Harrison, 18th/e, p. 1549, 1550; 17th/e, p. 1174)* Amongst the given options, only Candida causes oral lesion in AIDS patient.