Why is a vitamin K injection typically administered shortly after birth?

• A. Because newborns lack gut bacteria that synthesize vitamin K, increasing risk of bleeding disorders unless supplemented
• B. To provide long-term immunity against common neonatal infections via vitamin-mediated antibody production
• C. To prevent rickets by ensuring adequate calcium absorption in the neonatal gut
• D. To directly accelerate weight gain and enhance fat deposition during the first week of life

Answer: (A)