**Core Concept**
In pediatric patients, the daily fluid maintenance requirement is calculated based on the child's weight, with the aim of replacing the fluid lost due to metabolic processes, urine production, and other factors. The World Health Organization (WHO) and other pediatric guidelines provide formulas to estimate fluid needs in children.

**Why the Correct Answer is Right**
The correct answer is based on the Holliday-Segar formula, which is widely used to estimate fluid needs in children. According to this formula, the daily fluid maintenance requirement for a child is approximately 100 mL/kg/day. For a 15 kg child, the calculation would be 100 mL/kg/day x 15 kg = 1500 mL/day. This formula takes into account the child's weight and provides an estimate of the fluid needed to maintain proper hydration.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely incorrect because it is too low for a 15 kg child.
**Option B:** This option may be a distractor, but it is not based on a widely recognized formula for pediatric fluid maintenance.
**Option C:** This option is likely incorrect because it is too high for a 15 kg child.

**Clinical Pearl / High-Yield Fact**
A commonly used mnemonic to remember the Holliday-Segar formula is "100 mL/kg/day = 1500 mL/day for a 15 kg child". This can be helpful in high-pressure exam situations.

**Correct Answer:** C. 100 mL/kg/day x 15 kg = 1500 mL/day