**Core Concept**
Anhydrous glucose is used in reduced osmolarity Oral Rehydration Solution (ORS) to treat dehydration caused by diarrhea, especially in children. This formulation aims to reduce the osmotic load on the gut and promote water absorption while minimizing the risk of hypernatremia.

**Why the Correct Answer is Right**
The use of anhydrous glucose in reduced osmolarity ORS is based on the concept of osmoregulation. Glucose acts as an osmotic agent, drawing water into the gut lumen through a facilitated diffusion mechanism mediated by the sodium-glucose cotransporter 1 (SGLT1) in the intestinal epithelium. This process helps to rehydrate the body and replenish lost electrolytes. The reduced osmolarity formulation ensures that the solution does not cause an excessive shift of water into the gut, thus minimizing the risk of hypernatremia.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not mention the specific type of glucose used in reduced osmolarity ORS. Anhydrous glucose is the correct formulation used in this context.
**Option B:** This option is incorrect as it refers to a different type of glucose that is not used in reduced osmolarity ORS.
**Option C:** This option is incorrect as it does not provide any relevant information about the type of glucose used in reduced osmolarity ORS.

**Clinical Pearl / High-Yield Fact**
Reduced osmolarity ORS containing anhydrous glucose is recommended by the World Health Organization (WHO) for the treatment of dehydration caused by diarrhea in children. This formulation has been shown to be effective in reducing the risk of hypernatremia and promoting rapid rehydration.

**Correct Answer:** A. Anhydrous glucose