An API client is implemented as a Mule application that includes an HTTP Request operation using a default configuration. The HTTP Request operation invokes an external API that follows standard HTTP status code conventions, which causes the HTTP Request operation to return a 4xx status code .
What is a possible cause of this status code response?
A . An error occurred inside the external API implementation when processing the HTTP request that was received from the outbound HTTP Request operation of the Mule application
B . The external API reported that the API implementation has moved to a different external endpoint
C . The HTTP response cannot be interpreted by the HTTP Request operation of the Mule application after it was received from the external API
D . The external API reported an error with the HTTP request that was received from the outbound HTTP Request operation of the Mule application
Answer: D