Answer: The answer is C- Movement of the abdomen with respiratory effort.
Explanation:
Adults require the coordinated use of the diaphragm, the intercostal muscles and the abdominal muscles for breathing.
However babies and young children make use of the abdominal muscles to pull the diaphragm down for breathing. Their intercostal muscles are not yet fully developed at birth. It is therefore easy to observe respiratory distress by observing the movement of the abdominal muscles.