An Azure Function needs to call external APIs using an access token stored as a secret named 'token' in an Azure Key Vault named 'mykeyvault'. What value should you place in the Azure Function App configuration to reference that secret?

The correct answer uses the Azure Key Vault reference syntax for App Service and Azure Functions. This syntax, @Microsoft.KeyVault(SecretUri=...), allows the function app to securely retrieve the secret from the specified Key Vault at runtime. The SecretUri points directly to the secret's full URI, including the vault name and secret name. The other options are incorrect because they do not follow the established syntax for referencing Key Vault secrets in Azure Function App configurations. KeyVault:mykeyvault;Secret:token and App:Settings:Secret:mykeyvault:token are not valid syntaxes. AZUREKVCONNSTR https://mykeyveult.vault.azure.net/secrets/token/ is also not the correct format for directly referencing a secret value in an application setting; it resembles a connection string prefix but is incomplete and incorrectly formatted for this purpose.