Okay, let's tackle this question about the glucose content in WHO ORS. The user mentioned that the correct answer is 75 mmol/L. First, I need to recall the composition of the WHO Oral Rehydration Solution. The standard formula includes sodium, potassium, chloride, citrate, and glucose. The glucose is crucial because it helps in the absorption of sodium and water via co-transport in the intestinal epithelium.

The core concept here is the osmolarity and the role of glucose in ORS. The WHO formula has a specific osmolarity to prevent gastrointestinal upset. I remember that the glucose concentration is 75 mmol/L, which contributes to the overall osmolarity. The options might include other values like 50, 100, or 150 mmol/L, which are incorrect. Each of these wrong options would need to be explained. For example, 50 mmol/L is too low to effectively drive sodium absorption, while 100 mmol/L might be from an older formula. The clinical pearl would stress the exact value and its importance in ORS efficacy. Also, mentioning that the current WHO guidelines use 75 mmol/L is key. I need to make sure the explanation is concise but covers all the points as per the user's structure.

**Core Concept**
The World Health Organization (WHO) Oral Rehydration Solution (ORS) contains **75 mmol/L glucose** to optimize sodium-glucose co-transport in the intestinal epithelium. This concentration ensures effective fluid and electrolyte absorption while maintaining an isotonic osmolarity (~311 mOsm/L).

**Why the Correct Answer is Right**
75 mmol/L glucose in WHO ORS facilitates **sodium-dependent glucose absorption** via the SGLT1 transporter in the small intestine. This process drives water absorption, preventing dehydration. The glucose concentration is carefully calibrated to avoid hyperosmolarity (which could worsen diarrhea) and to maximize rehydration efficiency. The total osmolarity of WHO ORS is 311 mOsm/L, achieved by combining glucose with 75 mmol/L Na⁺, 20 mmol/L K⁺, 100 mmol/L Cl⁻, and 10 mmol/L citrate.

**Why Each Wrong Option is Incorrect**
**Option A: 50 mmol/L** – Too low to saturate SGLT1 transporters, reducing sodium and water absorption efficacy.
**Option B: 100 mmol/L** – This reflects the older UNICEF ORS formulation (1975–2002), which had higher osmolarity (450 mOsm/L) and worsened diarrhea.
**Option C: 150 mmol/L** – Exceeds SGLT1 transporter capacity, leading to unabsorbed glucose and osmotic diarrhea.

**Clinical Pearl / High-Yield Fact**
Remember: **"75-75-100"** for WHO ORS – 75 mmol/L glucose, 75 mmol/L Na⁺, and 100 mmol/L Cl⁻. The updated formula (2002–present) is **isotonic** (311 mOsm/L), unlike

✓ Correct Answer: A. 75