Explanation
As the life of the project draws towards its end, there's often an increase in the number of change requests.
When change requests are made towards the end of a project, however, the cost and impact of the change increases significantly.
Answer D is incorrect. It's ideal for change requests, if they must happen, to happen at the launch of the project, not just at the end.
Answer A is incorrect. The best answer is that change requests must happen towards the end of project execution, not just project planning. Planning spans the entire life of the project.
Answer B is incorrect. Scope review happens early in the project and changes early in the project are easier to incorporate and manage than changes at the end of the project.

Explanation
Interface analysis is not an event-based elicitation technique. It is an elicitation technique that identifies interfaces between solutions and how the interfaces will interact.
Answer D is incorrect. A workshop is an event-based elicitation technique. Answer A is incorrect. A focus group is an event-based elicitation technique. Answer C is incorrect. An interview is an event-based elicitation technique.