C is right. It want to tell you to set application home zone of sharepoint to zone sfo. App home has priority and ensure that sharepoint will always start in that zone. Near it's database

B doesn't sound right because publishing SharePoint within each zone means that performance would be crappy in zones where the database isn't located. Remember, we want apps to be with their data. Making a published app reach out across a WAN for the database is slow. Asking an ICA connection to traverse the WAN to where the the app and data are located is fast. B is not the answer. D isn't quite right. If SharePoint fails to launch in SFO, we'd still like it to launch in other zones, despite less performance. A is just silly. Changing the process priority doesn't fix the architecture to improve performance across zones. C makes sense. We want applications to be with their data. Let's make SFO the home zone for SharePoint. https://docs.citrix.com/en-us/citrix-virtual-apps-desktops-service/manage-deployment/zones.html#manage-home-zones-for-applications

performance bottleneck here is SharePoint db, client must be as close to db as possible, so C is correct

Correct answer should be B (B. Publish SharePoint in an individual Delivery Group within each zone. Answer C is incorrect because if the application home zone is set to one of the three zones, then all users from all user groups will be redirected to the VDAs of that zone for launching the app, which is not what this scenario is asking for from a performance point of view.