Induction type instruments are commonly used in electrical engineering for measuring various electrical quantities. These instruments work on the principle of electromagnetic induction, where the movement of a conductor in a magnetic field induces a current.

In the given options, the correct answer is option C, Energy meter. Here's a detailed explanation:

Energy Meter:
- An energy meter is used to measure the amount of electrical energy consumed by a load over a specific period of time.
- It is an induction type instrument that utilizes the principle of electromagnetic induction to measure the energy consumption accurately.
- The energy meter consists of a rotating aluminum disc that is placed in a magnetic field. The disc rotates at a speed proportional to the amount of electrical energy being consumed.
- As the disc rotates, it interacts with a series of fixed coils that generate a magnetic field. This interaction induces eddy currents in the disc, which in turn create an opposing magnetic field.
- The opposing magnetic field exerts a torque on the disc, causing it to rotate. The rotational speed of the disc is directly proportional to the amount of energy being consumed.
- The energy meter is calibrated to measure the rotational speed of the disc and convert it into electrical energy units, such as kilowatt-hours (kWh).
- Energy meters are widely used in residential, commercial, and industrial applications to accurately measure and bill the electrical energy consumption.

Other options:
- Ammeter: An ammeter is used to measure electric current flowing through a circuit. It typically works based on the principle of magnetic induction or shunt resistance.
- Voltmeter: A voltmeter is used to measure the voltage across a circuit or component. It can be based on different principles such as electrostatic attraction, electromagnetic induction, or electronic amplification.
- Multimeter: A multimeter is a versatile instrument that combines the functionalities of an ammeter, voltmeter, and ohmmeter. It can measure various electrical quantities such as current, voltage, resistance, and continuity.

In summary, an induction type instrument is an energy meter, which is used for measuring electrical energy consumption accurately.