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: Medicine
In ataxia, telengiectasia which is seen- 
Select and explain. 
A. Ig G absent, B. Ig M absent, C. Ig A absent, D. Ig A structure abnormality
C: Ig A absent
Answer: C: Ig A absent 
Explanation: None