What restriction applies to nursing assistants regarding oxygen administration?

The correct choice states that nursing assistants cannot administer oxygen or change the flow rate. This restriction is in place because oxygen administration is considered a medical intervention that requires specialized training and knowledge. Nursing assistants are not qualified to determine the appropriate therapeutic levels of oxygen or to make clinical judgments regarding a patient's respiratory needs, which could lead to significant health risks if not managed properly.

Oxygen therapy must be overseen by licensed healthcare professionals, such as nurses or physicians, who can assess the patient's overall condition and make decisions based on medical guidelines. This ensures patient safety and adherence to legal and ethical standards in healthcare practice, recognizing the importance of controlled oxygen administration in various health conditions.

In contrast, the other options suggest actions that nursing assistants are not authorized to undertake, such as adjusting the flow rate or initiating therapy. These responsibilities fall outside the scope of practice for certified nursing assistants.