The answer is Anemometer.
Wind speed is measured using an instrument called an anemometer. Its most common form uses three or four cups fixed to spokes around a rotating shaft, and as wind pushes the cups around, the spin rate is translated into a speed value, usually shown in units like kilometres per hour or metres per second. You will find anemometers mounted at meteorological stations, on ships, at airports, and at sites being studied for wind turbine installation.
It helps to rule out the alternatives by knowing what each one actually does. An altimeter tells you height above sea level or ground level, useful for pilots and climbers. A chronometer is simply a very accurate clock, once essential for calculating longitude at sea. A dosimeter tracks exposure to radiation, a tool used to keep workers in nuclear or medical settings safe.
Since wind speed measurement is the job of the anemometer specifically, the correct choice is option 2.