Which of the following is a scenario where personal or on-premise gateway is required for refreshing datasets?

The scenario where a personal or on-premise gateway is required for refreshing datasets occurs when using an R script as a dataset source. This is because R scripts can often access local data or use packages that require data to be situated on a local or organizational network instead of the cloud. When the data resides on-premises or requires specific local setups to execute the R code, a gateway becomes necessary to facilitate the connection and ensure that the data can be refreshed in the Power BI service.

In contrast, connecting to a cloud database, fetching data from the web, and accessing local data files each have different requirements. Connecting to a cloud database or fetching data directly from the internet does not necessitate a gateway, as these sources are already accessible over the internet. Accessing local data files typically does not involve a gateway unless the files need to be refreshed regularly in a cloud environment, which would then require the use of a gateway specifically configured for that purpose.