The clamp-on AC ammeter consists essentially of a split-core and a rectifier-type instrument connected to the secondary winding of a particular type of transformer. Which type is used?

Correct Answer: Option C — current transformer

A clamp-on AC ammeter utilizes an integral current transformer (CT). The split-core acts as the transformer core, the clamped conductor serves as the single-turn primary winding, and the internal winding acts as the secondary, safely stepping down current for measurement.