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: Unknown
Child admitted with meningitis. Examination reveals gram negative diplococci. History of previous similar infection is present with same organism. Which of the following should be suspected? 
Select and explain. 
A. Complement deficiency, B. Immunoglobulin deficiency, C. T cell, D. 8 cell
A: Complement deficiency
Answer: A: Complement deficiency 
Explanation: Ans: A (Complement deficiency) Ref: Harrison's Principles of Internal Medicine, 17th edition, 2008, Chapter 136, pg: 911 and Nelson Textbook of Pediatrics, 19th editionExplanation:Defects in Complement SystemHost DefectDisease or Therapy Associated With DefectCommon Etioiogic Agent of InfectionC3* Congenital liver disease* SLE* Nephrotic syndrome* S. aureus* S. pneumoniae* Pseudomonas spp* Proteus spc.C5* Congenital* Neisseria spp.* Gram-negative rodsC6,C7,C8* Congenital,* SLE* Neisseria meningitidis* N. qonorrhoeaeAlternativepathway* Sickie cell disease* S. pneumonia* Salmonella spp.