Explanation:

Here’s the thing—let’s break down your options:

- Option 1: Betwa—That river flows mostly through Madhya Pradesh and Uttar Pradesh. No major dam called Hirakud here.

- Option 2: Mahanadi—This one’s the real deal. The Hirakud Dam sits proudly across the Mahanadi River, near Sambalpur in Odisha. In fact, it’s one of the world’s longest earthen dams, controlling floods and providing irrigation and hydroelectric power.

- Option 3: Krishna—Well known, but the dams here are Nagarjuna Sagar and Srisailam, not Hirakud.

- Option 4: Godavari—Big river, yes. But think of dams like Polavaram, not Hirakud.