This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nucleotides, Subject name: Biochemistry
THEME AND FOCUS: METABOLISM OF NUCLEOTIDES Case Study: A 17- month- old girl suffered from recurring respiratory infections. Injection of Diphtheria-Peussis-Tetanus (DPT) and Typhoid vaccine produced only a minimal response. The lysate of girl's erythrocytes were found to lack detectable adenosine deaminase activity. Her mother and father both showed approximately 50% of the normal red cell adenosine deaminase activity. Lead Question: Diagnose the disease. 
Select and explain. 
A. SCID, B. Crushing Muscular Trauma, C. Lesch -Nyhan Syndrome, D. Hypokalemia
A: SCID
Answer: A: SCID 
Explanation: Severe combined immunodeficiency(SCID) Crushing Muscular Trauma Lesch-Nyhan syndrome ADA (Adenosine Deaminase) deficiency Muscle cell damage resulting from pressure or crushing. Deficiency of Hypoxanthine Guanine Phospho Ribosyl Transferase (HGP). Required for both B & T lymphocytes. Hyperuricemia Self -mutilation