What is the result of a deficiency of factor IX?

A. Christmas disease: Christmas disease, also known as Hemophilia B, is caused by a deficiency in clotting factor IX. B. Hemophilia A: Hemophilia A is due to a deficiency in factor VIII, not factor IX. C. Idiopathic thrombocytopenic purpura: ITP is an autoimmune condition that causes platelet destruction, unrelated to clotting factor deficiencies. D. Thalassemia: Thalassemia is a genetic disorder affecting hemoglobin production, not clotting factors.