An enterprise is about to complete a major acquisition, and a decision has been made that both companies will be using the parent company's IT infrastructure. Which of the following should be done…

Updating the enterprise architecture (EA) is a subsequent step that occurs after understanding the current state and identifying gaps, as the EA needs to reflect the planned future state of the integrated environment.

Performing a Business Impact Analysis (BIA) assesses the impact of disruptions, which is important for business continuity planning, but it's not the immediate next step for technically merging infrastructures after a strategic decision has been made.

When an acquisition involves consolidating IT infrastructure under the parent company's standards, a gap analysis is crucial to identify differences between the acquired company's current systems, processes, and infrastructure and the parent company's target environment. This step determines what changes, integrations, or migrations are needed for alignment.

Developing a communication plan is a vital supporting activity throughout a merger but is not the direct technical or strategic action for addressing the infrastructure consolidation challenge itself.