**Core Concept**
DDAVP (Desmopressin) is a synthetic analogue of vasopressin, which is used to manage mild hemophilia A and type 1 von Willebrand disease. It works by stimulating the release of von Willebrand factor (VWF) and factor VIII from the endothelial cells, thereby increasing their plasma levels.

**Why the Correct Answer is Right**
DDAVP acts on V2 receptors in the renal tubules, leading to water retention and an increase in plasma volume. This results in an increase in the levels of VWF and factor VIII, which are essential for hemostasis. The increased levels of VWF and factor VIII are sufficient to manage mild hemophilia A and type 1 von Willebrand disease. DDAVP is not effective in severe hemophilia A or type 3 von Willebrand disease, as the underlying deficiency of factor VIII or VWF is too great.

**Why Each Wrong Option is Incorrect**
**Option A:** Corticosteroids are not used to manage hemophilia, as they do not affect the levels of clotting factors.
**Option C:** Vitamin K is essential for the production of clotting factors II, VII, IX, and X, but it is not used to manage mild hemophilia.
**Option D:** Tranexamic acid is an antifibrinolytic agent that stabilizes clots, but it does not increase the levels of clotting factors and is not used to manage mild hemophilia.

**Clinical Pearl / High-Yield Fact**
DDAVP should be used with caution in patients with heart disease, as it can lead to fluid retention and hyponatremia.

**✓ Correct Answer: B. DDAVP**