Concept:A wind vane is the instrument specifically designed to show the direction from which the wind is blowing.
Explanation:A cup anemometer measures wind speed, not wind direction.
A barometer measures atmospheric pressure and helps predict weather changes.
A wind anemometer, while related to wind, is generally used for measuring wind speed.
A wind vane, however, rotates freely to point into the wind, thereby indicating the direction of the wind.
Therefore, the instrument used for measuring wind direction is the wind vane.
Answer:D. Wind vane