Three testers joined the project team just before the end of the build.

Comprehensive and Detailed Explanation:

Upon receiving quality concerns, the project manager should:

B: Ask for additional data to assess the validity and scope of the defects.

D: Continue testing per the plan to gather more data and not delay progress unnecessarily.

E: Collaborate with the team to brainstorm root causes and next steps.

A is too drastic without evidence.

C may be premature if the issue can be handled by the team.