Patient with hemophilia A have bleeding disorder because of: (A) Lack of platelet count, (B) Lack of platelet adhesion, (C) Lack of factor VIII a during activation of factor X in coagulation coscade, (D) Release of thromboxane A2
Answer is C. Hemophilia A
X - linked disorder

90% cases - deficiency of factor 8
10% cases functional defect of factor 8

Factor VIII a complex is the most important activator of factor X required for conversion of prothrombin to thrombin.