An Azure service that is used to provision Windows and Linux virtual machines.
As per the documentation mentioned in the error message, it states
In general, NC-Series customers should consider moving directly across from NC sizes to NC T4 v3 sizes, Azure’s new GPU-accelerated platform for light workloads powered by NVIDIA Tesla T4 GPUs
So try choosing the size as "Standard_NC4as_T4_v3" and try creating the VM.
If you have existing VMs, then you could migrate by following steps.
https://learn.microsoft.com/en-us/azure/virtual-machines/n-series-migration#migration-steps
Hope this helps