How many oxygen masks are available for passengers at each PSU?

The correct answer is based on standard aviation safety protocols regarding the number of oxygen masks that are typically provided at each Passenger Service Unit (PSU) on commercial aircraft. Each PSU is designed to ensure that all passengers seated in that section of the aircraft have access to supplemental oxygen in an emergency situation. Generally, there are three oxygen masks available at each PSU, allowing for one mask for the passenger and an additional two masks to accommodate nearby seating arrangements, ensuring that a row can effectively cater to potential scenarios where multiple masks might be needed simultaneously.

The adherence to this standard is crucial for maintaining the safety and well-being of passengers, particularly in situations where cabin pressure is compromised. While other options suggest numbers greater than or less than three, they do not reflect the commonly accepted safety regulations and practices established across airline operations, which support the presence of three masks at each PSU.