Correct Answer - Option 1 : a and d
The permanent magnet moving coil (PMMC) instrument uses two permanent magnets to create a stationary magnetic field. These types of instruments are only used for measuring the DC quantities.
Electrolytic meters are exclusively DC ampere-hour meters, measuring an electric quantity directly and electric energy only indirectly, on the assumption that the pressure of the supply is constant.
Dynamometer type instrument is used for the measurement of A.C. as well as D.C. quantity. It is equally accurate on AC and DC circuits.
Shaded-pole type and induction type instruments are only used for AC measurements.