## Core Concept
The oral rehydration solution (ORS) is a type of fluid replacement used to prevent and treat dehydration, especially due to diarrhea. It contains specific amounts of salts and sugars to facilitate the absorption of fluids and electrolytes by the body. The composition of ORS is defined by the World Health Organization (WHO) and includes precise concentrations of sodium, potassium, chloride, glucose, and citrate.

## Why the Correct Answer is Right
The correct molar concentration of the oral rehydration fluid, as recommended by the WHO, is **75 mEq/L of sodium** and **75 mmol/L of glucose**. The osmolarity of the solution has been reduced over the years to make it more effective and safer. The reduced osmolarity ORS contains 245 mOsm/L, which helps in better absorption and less stool output. This composition corresponds to option **.

## Why Each Wrong Option is Incorrect
- **Option A:**
- **Option B:**
- **Option D:**

## Clinical Pearl / High-Yield Fact
A crucial point to remember is that the reduced osmolarity ORS, as recommended by the WHO, has a specific composition that includes **75 mEq/L of sodium** and **75 mmol/L of glucose**, making it more effective in treating dehydration caused by diarrhea.

**Correct Answer: .**