**Core Concept:** Energy requirement refers to the amount of energy needed by an individual to maintain body functions, grow, and reproduce. In the context of artificial feeding for infants, it is crucial to calculate the required energy to ensure proper growth and development.

**Why the Correct Answer is Right:**
A newborn infant requires approximately 130-150 calories per kilogram of body weight per day. This estimation is based on the concept of the "baby's energy reserve" theory which states that infants need a higher energy intake to compensate for the inability to store energy efficiently due to their developing adipose tissue. As the infant grows, the energy requirement decreases proportionally with body weight.

**Why Each Wrong Option is Incorrect:**
A. 100 calories per kilogram: This is too low as infants require a higher energy intake than adults, even though they have a lower resting energy expenditure.
B. 170 calories per kilogram: This is too high, as it exceeds the actual energy requirement for infants, leading to unnecessary weight gain and potential obesity.
C. 190 calories per kilogram: This is also too high, similar to option B.
D. 200 calories per kilogram: This is still too high, as it exceeds the actual energy requirement for infants.

**Clinical Pearl / High-Yield Fact:**
Infants require a higher energy intake compared to adults due to their developing adipose tissue and higher energy expenditure for growth and development. The energy requirement decreases as the infant grows and matures. Adequate nutrition is essential for growth, development, and overall health outcomes in infants.

**Correct Answer:** 130-150 calories per kilogram of body weight per day (Option A). This range takes into account the baby's energy reserve theory and ensures optimal growth and development in infants.