What should you do?

A company is migrating an existing on-premises third-party website to Azure. The website is stateless.
The company does not have access to the source code for the website. They do not have the original installer.
The number of visitors at the website varies throughout the year. The on-premises infrastructure was resized to accommodate peaks but the extra capacity was not used.
You need to implement a virtual machine scale set instance.
What should you do?
A. Use an autoscale setting to scale instances vertically
B. Create 100 autoscale settings per resource
C. Scale out by one instance when the average CPU usage of one of the instances is over 80 percent
D. Use Azure Monitor to create autoscale settings using custom metrics
E. Use an autoscale setting with unlimited maximum number of instances
F. Use a webhook to log autoscale failures