Which option is true when calculating round-trip delay in IP SLA operations？（）

• A、The processing time on the end routers is only assessed for operations that involve the responder.
• B、The processing time on the end routers is only assessed for operations that involve the transmitter.
• C、The processing time on the end routers is only assessed for operations that involve both the responder and the transmitter.
• D、The processing time on the end routers is not assessed for neither the responder nor the transmitter.