To reduce short circuit fault currents are used.

The correct answer is: A. reactors

Reactors are used to reduce short circuit fault currents by absorbing some of the energy of the fault current. This is done by creating a magnetic field that opposes the current flow. The larger the reactor, the more current it can absorb.

Resistors are not used to reduce short circuit fault currents because they would dissipate too much heat. Capacitors are also not used because they would store the energy of the fault current and could later release it, causing damage to the system.

Here is a more detailed explanation of each option:

• Reactors are used to reduce short circuit fault currents by absorbing some of the energy of the fault current. This is done by creating a magnetic field that opposes the current flow. The larger the reactor, the more current it can absorb.
• Resistors are used to reduce current flow, but they would dissipate too much heat if used to reduce short circuit fault currents. This is because the fault current is very high and would cause the resistor to overheat.
• Capacitors are not used to reduce short circuit fault currents because they would store the energy of the fault current and could later release it, causing damage to the system.

I hope this helps! Let me know if you have any other questions.