Answer:
B
Explanation:
Von Willebrand disease is the underlying cause of this patient's anemia, as indicated by the low von Willebrand factor activity. This is the most common hereditary bleeding disorder, occurring in roughly 1% of the population. Intranasal or intravenous desmopressin is appropriate treatment for most bleeding problems. Desmopressin works by causing release of von Willebrand factor from vessel endothelial cells.
Source: Wikipedia