Explanation
C: The spending limit in Azure prevents spending over your credit amount. All new customers who sign up for an Azure free account or subscription types that include credits over multiple months have the spending limit turned on by default. The spending limit is equal to the amount of credit and it can't be changed.
D: Turn on the spending limit after removing
This feature is available only when the spending limit has been removed indefinitely for subscription types that include credits over multiple months. You can use this feature to turn on your spending limit automatically at the start of the next billing period.
* Sign in to the Azure portal as the Account Administrator.
* Search for Cost Management + Billing.
* Etc.
Reference:
https://docs.microsoft.com/en-us/azure/cost-management-billing/manage/spending-limit