This is an example of low latency.
Following is a snippet from a Microsoft blog article.

Option A is incorrect since this is used to ensure that a service is running even in the event of a service failure.
Option B is incorrect since this is used to ensure that a service is running even in the event of a catastrophic loss.
Option C is incorrect since this is used to ensure that a service is scalable even when the load on the service increases.
https://azure.microsoft.com/en-us/blog/latency-is-the-new-currency-of-the-cloud-announcing-31- new-azure-edge-sites/