Which of the following choices best describes the method used to hold the mask in place while delivering ventilation via a BVM?

The E-C clamp method is the most effective technique for securing a bag-valve-mask (BVM) respiratory device while delivering ventilation. This technique involves using the thumb and index finger to form an 'E' shape with one hand, which helps maintain a solid grip on the mask, ensuring a proper seal over the patient's mouth and nose. The remaining fingers create a 'C' shape that supports the jaw, effectively preventing airway obstruction.

This method is crucial in situations where effective ventilation is needed swiftly, as it allows the rescuer to use one hand for the BVM while keeping the other hand free to manage the airway or any other tasks. The E-C clamp provides stability and helps ensure consistent, adequate ventilation without interruptions, making it a preferred choice in emergency situations.

Other techniques, such as the thumb grip technique, one-handed hold, or two-handed grip, may not provide the same level of control or seal as the E-C clamp. While these methods might be useful in specific scenarios, they can be less reliable for maintaining the necessary air-tight fit needed for optimal ventilation during CPR. Thus, the E-C clamp method stands out as the best practice for administering BVM ventilation effectively.