<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 4-year-old boy presents with a history of recurrent bacterial infections, including several episodes of pneumococcal sepsis. His 2 maternal uncles died after having had similar complaints. Lab investigations reveal an undetectable level of all serum immunoglobulins. Which of the following is the most likely diagnosis of this patient?? A: Common variable immunodeficiency, B: Hereditary angioedema, C: Chediak-Higashi syndrome, D: Bruton agammaglobulinemia, E: DiGeorge syndrome,  <response>: This is a patient with recurrent bacterial infections and undetectable serum immunoglobulin levels. The history of similar complaints in maternal uncles suggests an X-linked inherited disorder. Of the choices given, Bruton agammaglobulinemia is an X-linked disorder characterized by impaired B cell maturation and decreased immunoglobulin production. Common variable immunodeficiency can present similarly but is not X-linked. Hereditary angioedema causes recurrent swelling, not infections. Chediak-Higashi syndrome causes immunodeficiency along with other findings like partial albinism. DiGeorge syndrome is characterized by T cell defects, not B cellantibody defects. Therefore, Bruton agammaglobulinemia is the most likely diagnosis. D: Bruton agammaglobulinemia 