This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immune system, Subject name: Medicine
Diagnosis of X linked agammaglobuliflem should be suspected if- 
Select and explain. 
A. Absent tonsils and no palpable lymph nodes on physical examination, B. Female Sex, C. High Isohemagglutinins titers, D. Low CD 3
A: Absent tonsils and no palpable lymph nodes on physical examination
Answer: A: Absent tonsils and no palpable lymph nodes on physical examination 
Explanation: X-linked disorders Males have only one X chromosome; consequently, a daughter always inherits her father's X chromosome in addition to one of her mother's two X chromosomes. A son inherits the Y chromosome from his father and one maternal X chromosome. Thus, the characteristic features of X-linked inheritance are (1) the absence of father-to-son transmission, and (2) the fact that all daughters of an affected male are obligate carriers of the mutant allele