While standing an "at sea watch" onboard a modern rectified DC diesel-electric drive ship you notice the transformer core temperature slowly rising. What should be your FIRST action?

Correct Answer: Option A — check the transformer ventilation fans for proper operation

Transformer cooling relies on forced ventilation to dissipate heat generated by core and copper losses. A rising temperature indicates restricted airflow or fan failure. Per IEEE 45, verifying ventilation is the primary troubleshooting step to prevent insulation breakdown and catastrophic failure before escalating to load shedding or operational changes.