Final answer:
Sandra should download the .iso file format from Fedora's website to install it as a virtual machine, as it contains the entire operating system in a format that can be mounted and booted for installation. The correct option is B.
Step-by-step explanation:
Sandra is looking to download an image of Fedora to install it as a virtual machine on her Windows workstation. The file format she is likely to find available for download from Fedora's website that can be used as the source for booting and installing Linux as a VM is .iso.
This file format is a disc image file that contains the entire contents of a CD or DVD in a single file. It is a sector-by-sector copy of the actual disk data. The .iso file can be mounted as a virtual CD/DVD drive, allowing Sandra to boot the virtual machine from it and proceed with the Fedora installation.
Other file formats listed, such as .exe (executable files), .doc (document files), and .zip (compressed files), are not suitable for this purpose because they do not serve as bootable media for operating system installation.