What equipment is used to measure wind speed and direction?

The correct choice is an anemometer, which is specifically designed for measuring wind speed and direction. Anemometers typically use rotating cups or blades that catch the wind and spin, with the speed of rotation correlating to the wind speed. Some advanced anemometers also include features to determine the wind direction by incorporating a wind vane into their design.

While the barometer measures atmospheric pressure, the thermometer is used to measure temperature, and the hydrometer assesses the specific gravity of liquids, none of these tools are linked to wind measurements. Therefore, their functions are distinct and not applicable to the task of measuring wind speed and direction, solidifying the anemometer as the appropriate choice for this purpose.