Refer to the exhibits.
A Mule application has an HTTP Request that is configured with hardcoded values. To change this, the Mule application is configured to use a properties file named config.yaml.
What valid expression can the HTTP Request host value be set to so that it is no longer hardcoded?
A . ${training.host}
B . ${training:host}
C . #[training:host]
D . #[training.host]
Answer: A