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
PNH is associated with deficiency of: 
Select and explain. 
A. DAF (Decay accelerating factor), B. MIRL (Membrane inhibitor of reactive lysis), C. GPI Anchored Proteins (Glycosyl phosphatidyl Inositol anchored proteins), D. LFA (Lymphocyte function associated antigen)
C: GPI Anchored Proteins (Glycosyl phosphatidyl Inositol anchored proteins)
Answer: C: GPI Anchored Proteins (Glycosyl phosphatidyl Inositol anchored proteins) 
Explanation: Out of all the options given GPI Anchored Proteins is the best answer because DAF, MIRL and LFA are among the various GPI proteins found to be deficient in PNH. Ref: Wintrobe's Clinical Hematology By John P. Greer, Maxwell Myer Wintrobe, Page 1007.