This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Parasitology Pa 1 (Protozoology), Subject name: Microbiology
Giardiasis is associated with which immuno disorder 
Select and explain. 
A. Common variable immunodeficiency, B. C1 esterase deficiency, C. C8 deficiency, D. MAC deficiency
A: Common variable immunodeficiency
Answer: A: Common variable immunodeficiency 
Explanation: Risk factors of Giardiasis: Gammaglobulinemia Common variable immunodeficiency Selective IgA-deficiency. Cystic fibrosis Poor hygiene Elderly debilitated persons