Q. A concerned mother brings her 6-week-old infant to your office. She reports that the child had been very active up until the past 2 days. Over the past 2 days, the infant has been much sleepier and has not participated in breast feeding. On exam, the child appears dehydrated and sluggish. You send the child directly to the emergency room where a head CT is performed which shows intracranial hemorrhage. The child is admitted to the neonatal intensive care unit and ultimately is diagnosed with vitamin K deficiency bleeding. In vitamin K deficiency there is deficiency of all of the following EXCEPT which coagulation factor?