A 15–year–old female presented to the emergency department with history of recurrent epistaxis, hematuria and hematochezia. There was a history of profuse bleeding from the umbilicus stump at birth. Previous investigations revealed normal prothrombin time, activated partial thromboplastin time, thrombin time and fibrinogen levels. Her platelet counts as well as platelet function tests were normal but urea clot lysis test was positive. Which one of the following clotting factor is most likely to be deficient –