This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, 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: Mouth often involved in AIDS with hairy leukoplakia or Kaposi's sarcoma due to esophageal candidiasis It is also known as Oral thrush REF:ANANTHANARAYANAN TEXTBOOK OF MICROBIOLOGY 9EDITION PGNO.576