While performing a scheduled walkthrough at a construction site, the customer points out a discrepancy. Which of the following is the FIRST step that should be taken before submitting a change control

Consulting the project sponsor is a later step, usually after the change has been identified and some preliminary analysis (like impact) has been done.

When a customer points out a discrepancy, the very first step before considering formal change control, impact analysis, or consulting stakeholders, is to clearly identify and define the nature of the discrepancy. This involves understanding what the customer observed, what they believe is wrong, and what they are requesting to be changed. Without a clear identification of the change, subsequent steps like feasibility studies or impact analyses cannot be accurately performed.

A feasibility study evaluates if the change can be done, but this comes after understanding what the change is.

An impact analysis assesses the effect of the change on scope, schedule, cost, etc., but this requires a clear understanding of the change itself first.