**Core Concept**
The management of diarrhea in children involves the use of zinc supplementation to reduce the duration and severity of the illness, as well as to prevent future episodes. Zinc plays a crucial role in maintaining the integrity of the intestinal mucosa and enhancing the immune response.

**Why the Correct Answer is Right**
Zinc supplementation is recommended for children with diarrhea to reduce the duration of the illness by 20-30%. The World Health Organization (WHO) recommends a dose of 20 mg of zinc per day for 10-14 days for children aged 6-59 months. This dose is based on the concentration of zinc in the child's diet and the severity of the illness. The mechanism of action involves the enhancement of the intestinal barrier function, reduction of inflammatory cytokines, and modulation of the gut microbiome.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct dose of zinc.
**Option B:** This option is incorrect because it is not the recommended duration of zinc supplementation.
**Option C:** This option is incorrect because it does not account for the child's age and weight.

**Clinical Pearl / High-Yield Fact**
It is essential to note that zinc supplementation should be initiated within 14 days of the onset of diarrhea, as the efficacy of zinc in reducing the duration of the illness decreases if treatment is delayed.

**Correct Answer:** C. 10-20 mg per day for 10-14 days