A tug is best positioned for towing and maneuvering on rivers and other restricted waters where wave action is limited when __________.

Correct Answer: Option D — directly astern and pushing the tow

Pushing the tow from directly astern provides the tug with maximum control and maneuverability in restricted river waters. This configuration allows the tug to steer the tow effectively, counteracting current effects and ensuring precise positioning, which is superior to towing on a hawser in narrow or winding channels.