Emotional intelligence is the strongest skill to apply when an analyst detects that a customer is becoming annoyed. Emotional intelligence involves recognising emotional signals, understanding how those emotions may influence the interaction, regulating one's own response, and adapting communication appropriately. The SDA v9 curriculum specifically links emotional intelligence with rapport, conflict management, and negotiation. An analyst who recognises increasing frustration can change tone, acknowledge the customer's concern, demonstrate appropriate empathy, clarify what is happening, and focus the conversation on constructive next steps. This can prevent irritation from developing into open conflict. Assertiveness can be useful for maintaining appropriate boundaries or communicating clearly, but it does not provide the broader emotional awareness required in this situation. Call management provides structure to an interaction but does not specifically address the customer's emotional state. Closed questioning is principally an information-gathering technique used to obtain specific facts. SDA v9 identifies emotional intelligence as important to conflict management, while the curriculum includes rapport, communication, conflict management, and negotiation as connected analyst competencies.