I'm following Fred's How to Safely Test-Drive Win 10--step by step using VirtualBox. When I try to create a virtual machine the only versions of Windows that come up to be selected are 32-bit. My machine is running 64-bit Win8.1. I downloaded the 64-bit version of Win10. I can't figure out how to get the selections to show 64-bit.

Appreciate any insight to this.