B: To access a key vault during template deployment, set enabledForTemplateDeployment on the key vault to true.
D: The user who deploys the template must have the Microsoft.KeyVault/vaults/deploy/action permission for the scope of the resource group and key vault.
Incorrect Answers:
E: To grant access to a user to manage key vaults, you assign a predefined key vault Contributor role to the user at a specific scope.
If a user has Contributor permissions to a key vault management plane, the user can grant themselves access to the data plane by setting a Key Vault access policy. You should tightly control who has Contributor role access to your key vaults. Ensure that only authorized persons can access and manage your key vaults, keys, secrets, and certificates.
Reference:
https://docs.microsoft.com/en-us/azure/azure-resource-manager/templates/key-vault-parameter
https://docs.microsoft.com/en-us/azure/key-vault/general/overview-security