What technique is used to gather information subtly about individuals or missions?

The correct answer, elicitation, is a method used to gather information discreetly. This technique relies on casual conversation and social interactions rather than direct questioning. Through seemingly innocuous dialogue, a person practicing elicitation can lead the conversation to draw out useful information about individuals, their backgrounds, or details related to specific missions without raising suspicion. This subtlety makes it an effective tool for obtaining information while maintaining a level of plausible deniability.

Surveillance, while a valuable intelligence-gathering technique, involves closely monitoring individuals or activities and does not emphasize the indirect and conversational nature of elicitation. Interrogation, on the other hand, is a more confrontational method aimed at obtaining information through questioning, typically under duress or via a structured process, making it less about subtlety and more about direct engagement. Interviewing is a broader term that can encompass various types of information gathering, including elicitation, but it does not specifically refer to the subtlety or indirect hints that characterize elicitation.