What describes how nasals are produced in the vocal tract?

To understand why the choice that states "the oral cavity is closed while the velopharyngeal port is open" is correct, it's important to consider the anatomy and physiology of nasal sound production.

Nasals are produced when the airflow is directed through the nasal cavity. For this to occur, the velopharyngeal port, which is the gateway between the nasal cavity and the oral cavity, must be open. This allows the sound to resonate in the nasal cavity, producing the characteristic nasal sounds such as /m/, /n/, and /ŋ/.

At the same time, the oral cavity needs to be closed off to prevent air from escaping through the mouth, directing it solely through the nose. This closure is typically achieved by the lips coming together (as with /m/) or by the tongue making contact with the roof of the mouth (as with /n/ and /ŋ/).

In summary, the correct answer accurately describes that, during the production of nasal sounds, the oral cavity is closed, enabling the airflow to be redirected through the nasal cavity via the open velopharyngeal port, which is essential for producing these sounds effectively.