The enlargement of both nasal openings during inspiration is known as:

Rationale: A. Nasal grunting is a sound produced during exhalation due to partial airway obstruction, not visible enlargement of the nostrils. B. Nasal stridor refers to a high-pitched sound during breathing caused by upper airway obstruction, not the physical widening of nasal openings. C. Nasal flaring is the visible enlargement of both nostrils during inspiration, often seen in infants and young children as a sign of respiratory distress. It helps reduce airway resistance and increase airflow. D. Nasal obstruction is a blockage of nasal passages and does not describe the outward flaring of nostrils.