The correct answer is (c) Learn about problem domain at the later stages. In stakeholder needs elicitation, the heuristics (practical methods) for effective requirements gathering include: Determining stakeholder goals as the context is essential for understanding their needs. Studying user tasks helps identify what stakeholders actually do and need. However, learning about the problem domain at the later stages is NOT a heuristic for needs elicitation - it should be done during the initial stages of requirements gathering to properly understand the context and create suitable solutions. In software architecture and requirements planning, domain knowledge must be acquired early to inform proper elicitation techniques. Therefore, (c) is the incorrect heuristic among the options given, making it the correct answer to this question.