Which of the following is a sign of hypoglycemia in infants?

A weak, high-pitched cry in infants is a recognized sign of hypoglycemia. When an infant's blood sugar levels drop too low, various physiological responses occur. One such response can manifest as changes in cry. Specifically, a weak, high-pitched cry may indicate that the infant is in distress, which can result from insufficient glucose fueling the brain, leading to alterations in normal behavior and communication.

This symptom is significant because it highlights the infant's need for immediate attention. Newborns and young infants may not show many overt signs of illness, so atypical crying patterns can be critical indicators of underlying issues such as hypoglycemia.

While the other choices do not reflect signs of hypoglycemia—such as high energy levels or stable feeding patterns, which could imply adequate glucose levels—this weak cry distinctly signals the potential need for further assessment and intervention in the case of low blood sugar.