An anemometer is an instrument for measuring

An anemometer is a tool used to measure the speed of the wind. It is not used to measure relative humidity, altitude, turbidity, or salinity. Anemometers are important tools used by meteorologists to study the weather. They come in different types, including cup anemometers, vane anemometers, and sonic anemometers. Cup anemometers have three or four cups that spin around as the wind blows, while vane anemometers have a tail that aligns with the direction of the wind. Sonic anemometers use sound waves to measure the wind speed. Knowing the wind speed can help in predicting weather patterns and understanding the effects of wind on the environment. Therefore, the correct answer to this question is option C: wind speed.