$448.$ A technician installed Windows $10$ on a workstation. The workstation only has $3\mathrm{.}5$GB of usable RAM, even though the technician installed $8$GB$.$ Which of the following is the MOST likely reason this system is not utilizing all the available RAM?

A$.$ The system is missing updates.

B$.$ The systems utilizing a $32-$bit OS$.$

C$.$ The system's memory is failing.

D$.$ The system requires BIOS updates