Option A, anemometer, is the right answer.
Among the given options option A is right as an anemometer is a device that measures the speed of the wind and not the air pressure.
Both options B and C are used to measure the air pressure. Where the aneroid barometer measures the fluctuations in atmospheric pressure without using the liquid. And the mercury barometer measures the fluctuations in atmospheric pressure with the use of a glass partly filled with mercury, including its wide end lounging in a vessel of mercury.