What key must be configured for Sensor Deployment on Windows OS?

The correct choice indicates that the proper registry key for Sensor Deployment on Windows OS is where configurations relevant to DNS caching services are typically made. The Dnscache service is crucial for network connectivity and ensures that the CrowdStrike sensor can communicate efficiently with the Falcon platform to detect and respond to cyber threats.

When deploying sensors, the correct registry keys allow for appropriate configurations regarding how the sensor interacts with the operating system and the network. The settings under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Dnscache can be specifically important in scenarios where the sensor needs to resolve DNS queries, which is integral for the sensor's operation and its ability to report back to the Falcon platform.

The other registry paths listed relate to different services and do not directly pertain to the configurations necessary for proper sensor deployment. Therefore, focusing on the Dnscache key ensures that the necessary services for communication and functionality of the Falcon sensor are correctly set up.