A key to increasing supply chain management integration is to:

Supply chain integration involves aligning and coordinating processes, information, and strategies among legally separate organizations to act as a unified entity. A key to achieving deep integration is to elevate relationships with key suppliers from purely transactional to strategic partnerships. Having critical component suppliers share in strategy development and implementation ensures that objectives are aligned, fosters open communication, and builds the mutual trust necessary for seamless collaboration. This collaborative approach is more fundamental to integration than any single technology or operational tactic.

B. An Enterprise Resources Planning (ERP) system is a tool that primarily facilitates internal integration and does not guarantee integration between different companies.
C. A Warehouse Management System (WMS) is a specialized tool for managing a single function and is too narrow to drive overall supply chain integration.
D. A push strategy is forecast-driven and can cause the bullwhip effect, a symptom of poor integration; integrated chains often use pull strategies.

- APICS CSCP Learning System, Version 5.0 (2022), Module 2, Section A, Topic 1, "Concepts in Supply Chain Management." This topic describes the evolution of supply chain relationships from transactional to highly integrated strategic alliances.

- Lambert, D. M., & Cooper, M. C. (2000). Issues in Supply Chain Management. Industrial Marketing Management, 29(1), 65-83. https://doi.org/10.1016/S0019-8501(99)00113-3. The paper emphasizes that managing relationships and integrating processes with key partners are core components of SCM.