How many portable battery-powered megaphones are required on an air carrier airplane with a seating capacity of 150 passengers when 75 passengers are carried?

In an air carrier airplane with a seating capacity of 150 passengers, regulations require that two portable battery-powered megaphones be available to ensure effective communication and safety in the event of an emergency. This is particularly important as passengers must be directed to evacuate or follow safety protocols under stressful situations where clear and loud communication is key.

The correct choice of having one megaphone at the forward end and the other at the most rearward location addresses the need for coverage throughout the entire cabin. By positioning one megaphone at the front and another at the rear, it ensures that the flight crew can effectively communicate with all passengers regardless of where they are seated. This dual positioning allows for clear instruction and enhances safety measures by ensuring that signals can reach all passengers, particularly in larger aircraft.

The other options do not fulfill the requirement of having adequate communication across the whole passenger area. There may be cases where only one megaphone is provided, but that would compromise the communication efficacy in an emergency situation. Hence, the decision to have two megaphones at these strategic locations best satisfies safety regulations and the practical needs of managing passenger safety.