 Explanation:

Version/source control ensures that all code changes are tracked, and previously remediated flaws do not reappear.

Without robust source control practices, outdated or insecure code can inadvertently be reintroduced.

 Why Other Options Are Less Likely:

A. Ineffective configuration management controls: This pertains to system configurations, not application code.

B. Lack of change management controls: Change management addresses overall process but does not specifically prevent code reintroduction.

D. High turnover in the development department: While turnover may contribute to the issue, the root cause is inadequate version/source control.

 EC-Council CISO Reference:

Effective development practices, including version control, are emphasized as critical to maintaining application security.