## **Core Concept**
The World Health Organization (WHO) and UNICEF have formulated a standard composition for Oral Rehydration Solution (ORS) to treat dehydration caused by diarrhea. The solution contains essential salts and minerals, including sodium and potassium, in specific concentrations to facilitate optimal absorption.

## **Why the Correct Answer is Right**
The correct concentration of potassium in the standard ORS is 1.5 mmol/L, which translates to 75 mEq/L or 3.45 mmol/L (or 135 mg/L or 0.135 g/L, which can also be represented in micrograms as 135,000 micrograms/L). Among the given options, the value corresponds to 75 mmol/L or 3.0 mEq/L or 117 mg/L, which seems to be closest to the actual value when converted to micrograms and matched with available choices.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option does not match the known concentration of potassium in ORS.
- **Option B:** Similarly, this does not align with the standard potassium concentration.
- **Option D:** This option also does not correspond to the correct concentration of potassium.

## **Clinical Pearl / High-Yield Fact**
A crucial point to remember is that the standard ORS composition as recommended by WHO includes 75 mEq/L of potassium. This specific concentration is critical for effectively treating dehydration while also replacing lost electrolytes.

## **Correct Answer:** .