**Core Concept**
ReSoMal is a specialized rehydration solution designed for children with malnutrition, particularly in resource-limited settings. It aims to provide essential electrolytes, including sodium, to prevent and correct dehydration and electrolyte imbalances.

**Why the Correct Answer is Right**
The sodium content in ReSoMal is crucial for replenishing sodium stores in malnourished children, who often have impaired renal sodium conservation mechanisms. The correct sodium concentration helps to prevent hyponatremia, a common complication in this population. The sodium level in ReSoMal is set to promote sodium retention and minimize the risk of hyponatremia.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately reflect the sodium content in ReSoMal. The actual sodium concentration in ReSoMal is higher than what is listed in this option.

**Option B:** This option is incorrect as it implies a lower sodium concentration than what is recommended for ReSoMal. A lower sodium level may lead to hyponatremia in malnourished children.

**Option C:** This option is incorrect as it suggests an even lower sodium concentration than option B. A sodium level this low may exacerbate hyponatremia in malnourished children.

**Option D:** This option is incorrect as it implies a sodium concentration that is too high for ReSoMal. Excessive sodium can lead to hypernatremia, which is also a concern in this population.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the sodium content of ReSoMal is specifically designed to address the unique needs of malnourished children. A sodium concentration that is too low or too high can lead to serious electrolyte imbalances.

**Correct Answer:** C. 75 mmol/L