Which API object and attribute should be used to retrieve the status of the API call?

NTO is using an asynchronous SOAP API call to the TriggerSend object to send order confirmation email to their customers .

Which API object and attribute should be used to retrieve the status of the API call?
A . Result Object and EmailAddress
B. Result Object and ConservationID
C. ResultItem Object and OrderID
D. ResultItem Object and RequestID

Answer: D