If project is coming to completion and a major change request comes from the customer, that needs more funds then do you discuss with customer and try to understand why its needed and is in scope or not ? OR do you discuss with sponsor since this needs a lot of funds and project is about to complete ? Please provide your feedback to clarify my fundamentals.

Mostly before issuing a change request we want to analyze the impact, right ? thats what i thought and below is a question that i got wrong. I marked answer 2 but the right one is 4