What should you always do before giving an infant juice and why?

A) Dilute it with water to reduce sugar content, to prevent gastrointestinal discomfort.
B) Warm it up to room temperature, to prevent potential cold-induced digestive issues.
C) Check with a pediatrician, to ensure it is safe and appropriate for the infant's age and health.
D) Mix it with formula or breast milk, to provide additional nutrients and calories.