The answer is E, sphygmomanometer. A sphygmomanometer is a device used to measure blood pressure. The other four options are all devices used to measure physical quantities related to the weather.
A thermocouple is a device used to measure temperature. It works by converting heat energy into electrical energy.
A hygrometer is a device used to measure humidity. It works by measuring the amount of water vapor in the air.
An anemometer is a device used to measure wind speed. It works by measuring the speed of the air flowing past it.
A seismograph is a device used to measure earthquakes. It works by measuring the vibrations caused by the earthquake.