Exam CBAP topic 1 question 426 discussion

A company with a big information technology (IT) department has hired a lead business analyst (BA) to enhance its business analysis practices. The lead BA discovers that sponsors are not satisfied with project outcomes. Developers complain about incomplete, ambiguous, and changing requirements. All stakeholders, including project managers, are blaming long cycles of analysis for the delays. The business analysts, in turn, feel overwhelmed with the number of projects and frustrated by the lack of collaboration from reviewers of their deliverables. All of the evidence is anecdotal and none of the groups could strongly substantiate their options.
Even after dozens of reviews, some stakeholders refuse to sign off on the requirements specification documents because of a few questionable requirements.
This puts the projects at risk and creates tension between the participants. What should the lead BA do first?