<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 14-year-old boy presents with his mother complaining of a swollen, red, painful left knee. His physician aspirates the joint and discovers frank blood. The patient denies a recent history of trauma to the knee. Upon further discussion, the mother describes that her son has had multiple swollen painful joints before, often without evidence of trauma. She also mentions a history of frequent nosebleeds and gum bleeding following visits to the dentist. Which of the following is the most likely underlying diagnosis?? A: Hemophilia A, B: Hemophilia B, C: Hemophilia C, D: Factor VII deficiency, E: Child abuse,  <response>: This is a clinical case of a 14-year-old boy with recurrent hemarthrosis bloody joint fluid without history of trauma, along with other bleeding symptoms like nosebleeds and gum bleeding. The key findings are spontaneous hemarthrosis and a personal and family history of bleeding, which are classic for hemophilia A and B. Hemophilia A and B are X-linked recessive bleeding disorders caused by deficiencies in clotting factors VIII and IX, respectively. They commonly present in males with spontaneous bleeding episodes, especially hemarthrosis, that are disproportionate to any trauma. The other options can be ruled out: hemophilia C is a rare, autosomal recessive disorder, while factor VII deficiency and child abuse would not explain the recurrent joint bleeds. Therefore, the most likely diagnosis is hemophilia A or B.A: Hemophilia A 