**Core Concept**
The World Health Organization (WHO) recommends a specific amount of Oral Rehydration Solution (ORS) to be given to children with dehydration in the first 4 hours to prevent further dehydration and promote rehydration. This recommendation is based on the severity of dehydration and the child's weight.

**Why the Correct Answer is Right**
The correct amount of ORS is based on the child's weight and the severity of dehydration. In children with some dehydration, the WHO recommends administering 75 milliliters per kilogram of body weight over 4 hours. This amount helps to replace lost fluids and electrolytes, and promotes rehydration. The ORS solution contains salts, sugars, and other essential electrolytes that help to replenish the body's stores.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not take into account the child's weight and the severity of dehydration. Administering a fixed amount of ORS without considering these factors may lead to over- or under-rehydration.
**Option B:** This option is incorrect because it recommends a higher dose of ORS than necessary for children with some dehydration. This may lead to over-rehydration and potentially cause complications such as hyponatremia.
**Option C:** This option is incorrect because it recommends a lower dose of ORS than necessary for children with some dehydration. This may lead to under-rehydration and potentially cause dehydration to worsen.

**Clinical Pearl / High-Yield Fact**
Remember that the WHO recommends the following amounts of ORS for children with dehydration:
- Some dehydration: 75 milliliters per kilogram of body weight over 4 hours
- Moderate dehydration: 50-100 milliliters per kilogram of body weight over 4 hours
- Severe dehydration: 100 milliliters per kilogram of body weight over 4 hours

**Correct Answer:** C. 75 mL/kg over 4 hours