Which type of relay represents the phasor difference of two or more similar electrical quantities exceed a predetermined value? 

The correct answer is option 2

Concept :

Differential relay:

• A differential relay is one that operates when the phase difference of two or more two similar electrical quantities exceeds a pre-determined value.
• Thus current differential relay is one that compares the current entering a section of the system with the current leaving the section
• under normal operating conditions, two currents are equal but as soon as the fault occurs this condition no longer applies
• the difference between incoming and outgoing currents are arranged to flow through the operating coil of the relay.
• If a differential relay is equal to or greater than the pick value, the relay will operate and open the circuit breaker to isolate the faulty section.