Explanation
The document that contains the essential elements of effective processes and describes an improvement path considering quality and effectiveness is Capability Maturity Model Integration (CMMI). This is because CMMI is a framework that defines five levels of process maturity, from initial to optimized, and provides best practices and guidelines for improving the quality and effectiveness of processes across different domains, such as software development, service delivery, or cybersecurity. The other options are not documents that contain the essential elements of effective processes and describe an improvement path considering quality and effectiveness, but rather different types of documents or tools that provide guidance or recommendations for implementing policies or controls, such as Balanced Scorecard (B), ISO 27004:2009 C, or COBIT 5 (D).