**Core Concept**
Hemophilia is a genetic disorder characterized by the deficiency of clotting factors, leading to impaired blood coagulation. The treatment involves replacing the deficient clotting factor to achieve hemostasis. The choice of drug depends on the severity and type of hemophilia.

**Why the Correct Answer is Right**
The correct answer is **Desmopressin (DDAVP)**, which is used to treat mild hemophilia A. Desmopressin works by releasing von Willebrand factor (vWF) and factor VIII from storage sites, thus increasing their levels in the bloodstream. This is particularly useful in mild hemophilia A, where the factor VIII levels are not severely deficient. However, it is not effective in severe hemophilia A or hemophilia B.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because Epsilon Aminocaproic Acid (EACA) is an antifibrinolytic agent used to prevent excessive bleeding, not to treat hemophilia.
* **Option B:** This option is incorrect because Factor VIII concentrate is used to treat severe hemophilia A, not mild hemophilia.
* **Option C:** This option is incorrect because Factor IX concentrate is used to treat hemophilia B (Christmas disease), not mild hemophilia A.

**Clinical Pearl / High-Yield Fact**
It's essential to note that desmopressin can cause fluid retention and hyponatremia, particularly in patients with underlying heart or kidney disease. Therefore, careful monitoring is necessary when using this medication.

**Correct Answer:** D. Desmopressin (DDAVP)