A. If a guest OS doesn't support Hyper-V's Dynamic Memory capability, the VM will see the initial memory that was set for the VM. But that memory will not be increased based on usage, because it lacks the component to notify Hyper-V of its memory usage and the kernel enlightenment to add memory granted through Dynamic Memory.
A quick way to check if the VM OS will use Dynamic Memory is to open Device Manager (devmgmt.msc) in the guest OS and expand System devices. You should see a Virtual Dynamic Memory device. If the Memory Available column in the Hyper-V UI is blank, it means the Dynamic Memory guest component is not functioning correctly.