**Core Concept**
The calorie requirement of a child is determined by their age, weight, and activity level, and is essential for growth and development. The recommended daily energy intake for children varies based on these factors, and underestimating or overestimating calorie needs can lead to growth abnormalities or obesity.

**Why the Correct Answer is Right**
The correct answer, 1250 kcal, is based on the World Health Organization's (WHO) recommendations for daily energy intake for children. According to the WHO growth charts, a child weighing 15 kg requires approximately 1200-1300 kcal per day, with 1250 kcal being a suitable estimate for a moderately active child. This energy requirement is essential for supporting growth, maintaining body weight, and providing energy for physical activity.

**Why Each Wrong Option is Incorrect**
**Option A:** 1150 kcal is too low to meet the energy needs of a child weighing 15 kg, which may lead to inadequate growth and development.
**Option C:** 1450 kcal is excessive for a child of this weight, potentially leading to obesity and other metabolic problems.
**Option D:** 1550 kcal is also too high, as it exceeds the recommended daily energy intake for a child of this weight and age.

**Clinical Pearl / High-Yield Fact**
It's essential for pediatricians to assess a child's energy needs regularly, taking into account factors such as age, weight, height, and activity level, to ensure they receive the optimal amount of calories for growth and development.

**✓ Correct Answer: B. 1250 kcal**