This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Adenosine deaminasc deficiency is seen in the following - 
Select and explain. 
A. Common variable immunodeficiency, B. Severe combined immunodeficiency, C. Chronic granulomatous disease, D. Nezelof syndrome
B: Severe combined immunodeficiency
Answer: B: Severe combined immunodeficiency 
Explanation: Robbins basic pathology 6th edition. Chapter Diseases of immunity. page no. 235. Severe Combined Immunodeficiency Diseases(SCID) is autosomal recessive , most common cause being deficiency of adenosine deaminase enzyme(ADA).