Final answer:
Do not place the ELT switch to the 'arm' position when towing the aircraft to avoid accidental activation. The correct position is 'off' to prevent false distress signals during ground movement.
Step-by-step explanation:
Do not place the switch at the ELT unit to the arm position when towing the aircraft; this may cause inadvertent triggering of the ELT. The correct option is 3) arm. The Emergency Locator Transmitter (ELT) is a device designed to transmit a distress signal in the event of an aircraft accident. Placing the ELT switch to the arm position means that the unit is active and will transmit if it detects motion or force consistent with a crash. When the aircraft is being towed, vibrations and movements could potentially activate the ELT, resulting in a false alarm and unnecessary search and rescue operations. The best practice is to ensure that the ELT switch is set to the off position prior to moving the aircraft to prevent accidental activation.