When developing a business case for an enterprise resource planning (ERP) implementation, which of the following, if overlooked, causes the GREATEST impact to the enterprise?

While important, poor vendor selection primarily impacts project cost, timeline, and support quality, rather than directly causing operational disruption from system integration issues itself.

The salvage value of legacy hardware is a financial consideration, which has a monetary impact but does not directly disrupt business operations or the functionality of the new ERP system.

ERP systems are inherently designed to integrate various business functions. Failing to account for existing interdependent systems during planning will result in critical data flow issues, process breakdowns, and major integration challenges, severely impacting business operations and the success of the ERP implementation.

Adhering to IT best practices improves project efficiency and system quality, but overlooking them typically leads to suboptimal project management or less secure/efficient systems, not the immediate, large-scale operational failure caused by ignored interdependencies.