Concept:A pyrometer detects temperature by sensing the heat radiation an object emits.Explanation:Thermal radiation is the infrared energy released by any hot object.A pyrometer thermometer measures this emitted energy from a distance without touching the object.Other thermometers require direct contact or use changes in electrical resistance or gas pressure.Since the question specifies measurement from emitted thermal radiation, the correct device is a pyrometer thermometer.Answer:A. Pyrometer thermometer