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
Adenosine deaminase deficiency is seen in the following- 
Select and explain. 
A. Common variable immunodeficiency., B. Chronic granulomatous disease, C. Nezelof syndrome, D. Severe combined immunodeficiency
D: Severe combined immunodeficiency
Answer: D: Severe combined immunodeficiency 
Explanation: None