The question is about determining the correct frequency range used for electromagnetic (EM) drone jamming, specifically to disrupt the GPS and communication systems of drones. Let's analyze the given options:

1. Far-infrared frequency: This frequency range is typically used in thermal imaging and cannot effectively interrupt communication or navigation signals required for drone jamming.
2. Microwave frequency: This range, particularly bands like L-band (1-2 GHz) and C-band (4-8 GHz), is commonly used for communication jamming including GPS disruption. Microwave frequencies are well-suited for penetrating through the atmosphere and interrupting electronic signals.
3. Visible frequency: This range involves light visible to the human eye and is unsuitable for electronic signal disruption as it does not interfere with the communication spectrum.
4. Infrared frequency: Infrared is used in remote controls and thermal imaging but does not typically interfere with communication systems required for drone operation.

Given this analysis, the most effective frequency range for EM drone jamming is the Microwave frequency. This range is capable of disrupting communication and GPS signals due to its effective interaction with electronic devices.

Conclusion: The correct frequency range used for EM drone jamming is Microwave frequency. This is because it effectively disrupts the signals these drones rely on for guidance and control, unlike other frequencies which do not interfere with these systems.