What type of system architecture allows both local and cloud-based control in SCADA?

Fog computing is the correct choice because it provides a layer of computing that exists between the cloud and the devices at the edge, enabling local processing and decision-making. This architecture allows for data to be processed at various levels, both locally and in the cloud, facilitating real-time data analysis and control in SCADA systems.

In fog computing, data generated by field devices can be analyzed locally to reduce latency and minimize bandwidth use when sending data to the cloud for further analysis or storage. This makes it particularly effective for applications that require immediate response times and local control alongside higher-level cloud analytics.

Additionally, fog computing enhances flexibility and scalability, allowing organizations to tailor their computing and data processing needs to specific applications, thereby optimizing performance in SCADA systems.