To avoid battery drain on an EMS vehicle during a long response, which plan is correct?

• A. Prioritize essential systems and monitor battery voltage, but avoid external power.
• B. Switch off nonessential devices only if the battery is already low.
• C. Schedule high-draw devices to run simultaneously to reduce trips.
• D. Prioritize essential systems, switch off nonessential devices, monitor battery voltage, use external power if available, and schedule high-draw devices to minimize drain.

Answer: (D)