What can cause a spasm of the larynx and result in vomiting when inserted in a responsive patient?

The correct answer relates to the oropharyngeal airway, which can indeed provoke a spasm of the larynx in a responsive patient, leading to vomiting. The oropharyngeal airway is designed to maintain patency of the airway by preventing the tongue from occluding it. However, when it is improperly sized or inserted into a conscious patient, the presence of the device can trigger a gag reflex or laryngeal spasm due to the sensitivity of the airway structures. This reaction is more pronounced in a responsive patient who retains gag reflex abilities.

In contrast, nasal cannulas and bag-mask devices are typically used for oxygen delivery and ventilation, respectively, and do not induce spasm of the larynx in the same way. Endotracheal tubes, while they can also cause spasms if inserted improperly, are generally placed under controlled circumstances, often with sedation, to minimize such reflex actions. Therefore, the oropharyngeal airway stands out as the option that directly causes these reactions when the patient is awake and responsive.