Which core concept defines a specific way of satisfying one or more needs in a...

 The core concept that defines a specific way of satisfying one or more needs in a context is ‘Solution’. According to the Business Analysis Core Concept Model™ (BACCM™), a solution satisfies a need by resolving a problem faced by stakeholders or enabling stakeholders to take advantage of an opportunity. It is a specific response to a need within a given context, and it can vary significantly from one organization to another as different organizations or situations may require different solutions.

This explanation is consistent with the definitions provided in the Business Analysis Core Concept Model (BACCM™) as outlined by the International Institute of Business Analysis (IIBA) and the Business Analysis Body of Knowledge (BABOK) guide1234.