The best answer is C. Changes are approved after being moved to production.
ISACA guidance on change management emphasizes reviews, testing, approvals, and segregation of duties before moving changes forward. If changes are moved into production before approval, the organization has effectively bypassed one of the most important preventive controls in the change process. That creates direct risk of unauthorized, untested, or harmful changes reaching production.
Option A is a documentation weakness. Option B reduces efficiency and prioritization discipline. Option D is a concern for emergency changes, but it is still less severe than routinely approving changes only after implementation. In audit terms, post-production approval represents a fundamental control breakdown.
References (Official ISACA):
* ISACA Journal, Speeding Up Software Delivery With Effective Change Management.

Including the data warehouse in the impact analysis for any changes in the source system is the best way to prevent data quality issues caused by changes from a source system. A data warehouse is a centralized repository of integrated data from one or more source systems. An impact analysis is a technique of assessing the potential effects and consequences of a change on the existing system or environment. Including the data warehouse in the impact analysis can help to identify and mitigate any data quality issues that may arise from changes in the source system, such as data inconsistency, incompleteness, or inaccuracy. The other options are less effective ways to prevent data quality issues, as they may involve data quality alerts, approval for changes, or access restrictions. References:
CISA Review Manual (Digital Version), Chapter 5, Section 5.41
CISA Review Questions, Answers and Explanations Database, Question ID 226