An exception code can be triggered by the system or entered by a user.

Comprehensive and Detailed In-Depth Explanation:

External exception codes in SAP EWM handle deviations. Option B ("A business context") is correct as it defines where the code applies (e.g., picking), and option C ("An internal exception code") is correct because it maps the external code to an internal action, both configured in SPRO: SCM Extended Warehouse Management > Cross-Process Settings > Exception Handling > Define Exception Codes. Option A (workflow) is optional, and option D (execution step) is not a standard assignment.