Final answer:
An amplifier is not a transducer because it does not convert one form of energy into another but merely increases the signal's amplitude.
Step-by-step explanation:
The question is asking which item listed is not a transducer. A transducer is a device that converts one form of energy to another. For example, a microphone converts sound energy into electrical energy, while a loudspeaker does the opposite. On the other hand, an amplifier does not convert energy types, but instead increases the amplitude of a signal without changing its nature. Therefore, the correct answer is B) Amplifier, which is not a transducer; instead, it is a device that increases the power of a signal.