a. Fuse wire, bud conductor, rubber gloves, generator.
Generator. It converts mechanical energy into electric energy, the remaining three do not.
b. Voltmeter, Ammeter, gulvanometer, thermometer.
Thermometer. It measures temperature, the remaining three measure electrical quantities.
c. Loud speaker, microphone, electric motor, magnet.
Magnet. It exerts a force on a magnetic material, the remaining three convert one form of energy into another.