Final answer:
The phonemes m, n, and ing are produced with the velum closed, low intraoral pressure, and high rates of nasal airflow.
Step-by-step explanation:
The correct answer is Option C, which states that the phonemes m, n, and ing are produced with the velum closed, have low intraoral pressure, and high rates of nasal airflow. The velum is the soft part of the roof of the mouth, and when it is closed, it prevents air from escaping through the mouth and directs it through the nose, resulting in nasal sounds. The low intraoral pressure and high rates of nasal airflow are characteristic of nasal sounds.