Active listening helps establish the credibility of both the analyst and the Service Desk, making D the correct answer. Active listening involves concentrating on what the customer is communicating, checking understanding, responding appropriately, and demonstrating that the customer's information and concerns are being taken seriously.

Credibility develops because customers are more likely to trust an analyst who accurately understands their situation and avoids unnecessary repetition or assumptions. Effective listening also supports better diagnosis, improves understanding of customer needs, reduces misunderstanding, and helps the analyst identify emotional cues that may affect the interaction.

The other answers use absolute or misleading claims. Active listening cannot guarantee customer satisfaction because satisfaction is influenced by many factors. It can optimise an interaction, but it does not necessarily minimise every call's duration; appropriate investigation may require additional time. Nor does active listening mean that a customer's emotional condition remains unchanged. In fact, appropriate listening and empathy can positively influence that emotional state. SDA v9 specifically includes communication skills and the benefits of active listening.