ORS contains how much potassium –

**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 a mix of salts and sugars to help the body absorb fluids. The **World Health Organization (WHO)** recommends a specific composition for ORS, including the amount of potassium.

**Why the Correct Answer is Right**
The correct amount of potassium in ORS is 20 mmol/L. This is because potassium is an essential electrolyte that helps regulate fluid balance and blood pressure. During diarrhea, the body loses potassium, which can lead to **hypokalemia**. The potassium in ORS helps replace lost potassium and prevent further complications.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not match the recommended amount of potassium in ORS.
**Option B:** This option is also incorrect, as it is higher than the recommended amount.
**Option D:** This option is incorrect, as it is lower than the recommended amount.

**Clinical Pearl / High-Yield Fact**
It's essential to use the correct ORS formula to avoid complications, as incorrect electrolyte balance can lead to serious issues. The **WHO-recommended ORS** composition is a high-yield fact for exams.

**Correct Answer:** C. 20 mmol/L