A transmission line is protected by

Inrush protection
Distance protection
Time graded and current graded over current protection
Both (B) and (C)

The correct answer is: D. Both (B) and (C).

Inrush protection is used to protect a transmission line from damage caused by large inrush currents that can occur when a transformer is energized or when a fault occurs on the line. Distance protection is used to protect a transmission line from faults that occur beyond a certain distance from the relay. Time graded and current graded over current protection is used to protect a transmission line from faults that occur within a certain distance from the relay.

Inrush protection is typically implemented using an instantaneous overcurrent relay. This type of relay responds to the rate of change of current, which is high during inrush conditions. Distance protection is typically implemented using a directional overcurrent relay. This type of relay responds to the current flowing in a particular direction, which is different for faults that occur on the line and faults that occur beyond the line. Time graded and current graded over current protection is typically implemented using a time overcurrent relay. This type of relay responds to the current flowing in the line and the time that the current has been flowing.

All three of these types of protection are important for ensuring the safe and reliable operation of a transmission line.