D. They get a running start on the water to take flight.
Explanation - Diving ducks are those ducks that goes deep inside water and feed on the organisms present there. They have several adaptations such as highly tolerant to less oxygen content or asyphyxia, their body is structured in a way that the middle part is wider than the ends.
They also have large feet attached to short legs. Their wings are also compact. Diving ducks get a running start on the water to take flight.