Which option is most likely a cause of airway obstruction?

Laryngeal muscle paralysis is a significant cause of airway obstruction because it impairs the function of the muscles that control the opening and closing of the airway during breathing and swallowing. When the laryngeal muscles are paralyzed, they may not adequately protect the airway, leading to the potential for aspiration or blockage of airflow. This condition can result from various factors, including neurological disorders, trauma, or certain medical conditions.

In contrast, flexion and extension of the neck can also affect the airway, but they do not inherently cause paralysis of airway structures. While neck flexion may contribute to airway obstruction by compressing the trachea or affecting the alignment of the airway, it is not as direct a cause as muscle paralysis. Extension of the neck may sometimes facilitate breathing by opening the airway, thus reducing the chances of obstruction. This is why laryngeal muscle paralysis stands out as the most direct cause of airway obstruction in this context.