The correct answer is: C. Impedance relay
An impedance relay is a type of protective relay that uses the impedance of a circuit to detect faults. It is preferred for phase fault on short transmission line because it is more sensitive to faults that occur close to the relay.
An induction type relay is a type of protective relay that uses the principle of induction to detect faults. It is not preferred for phase fault on short transmission line because it is less sensitive to faults that occur close to the relay.
A reactance relay is a type of protective relay that uses the principle of reactance to detect faults. It is not preferred for phase fault on short transmission line because it is not as sensitive to faults that occur close to the relay as an impedance relay.
None of the above is not the correct answer because it does not specify a type of relay.