two currents
two voltages
two or more similar electrical quantities
none of the above
Answer is Wrong!
Answer is Right!
The correct answer is: A. two currents.
A differential relay is a type of protective relay that measures the vector difference between two or more electrical quantities, typically currents. It is used to protect electrical equipment from faults caused by unbalanced currents.
Option B is incorrect because a differential relay measures currents, not voltages.
Option C is incorrect because a differential relay measures two or more quantities, not just one.
Option D is incorrect because a differential relay is a type of protective relay.