Which step can an administrator take so that vSphere can access patch information if vCenter Server does NOT have Internet access?

Which step can an administrator take so that vSphere can access patch information if vCenter Server does NOT have Internet access? (Choose the best answer.)
A. Use a Web server on the vCenter Server machine to automate the transfer of files.
B. Install VMware vSphere Update Manager Download Service on a Windows server.
C. Use an offline ISO file to import patches to the vSphere Lifecycle Manager depot manually.
D. Install VMware vSphere Update Manager Download Service on a Linux server.