ANS:A - passive

LVDT (Linear Variable Differential Transformer) is a type of transducer used for displacement measurement. It is classified as a passive transducer. Passive transducers do not require an external power source to operate. In the case of an LVDT, it operates based on the principle of electromagnetic induction and does not require any external power source for its operation. Instead, it produces an output signal (voltage) proportional to the displacement of its core within its primary and secondary windings. So, the correct classification for LVDT used for displacement measurement is: Passive transducer