Final answer:
Engineer A should report the safety concerns to senior mine management and insist on implementing changes.
Step-by-step explanation:
Engineer A should choose option a. and report the safety concerns to senior mine management and insist on implementing changes. It is the responsibility of the Chief Engineer to prioritize the safety of the mine personnel and operations. By reporting the concerns and insisting on implementing changes, Engineer A can help prevent potential accidents or injuries and ensure the well-being of everyone working in the mine.