A is correct:
When the FILE:CONNECTIVITY error is thrown by the File Write operation, it is caught by the On Error Continue scope with the type FILE:CONNECTIVITY. Since it is an On Error Continue scope, it will set the payload to "FILE:CONNECTIVITY" which is then sent in a response with the HTTP 200 OK success status response code.
The error type mapping would affect the response, in a case of On Error Propagate, which then would not execute an error scope, would not set the payload and would not send a payload with the HTTP 200 OK success status response code.