## **Core Concept**
The question tests knowledge of the composition of Ringer's lactate solution, specifically the concentration of sodium ions (Na+). Ringer's lactate is a type of isotonic crystalloid solution commonly used in medical settings for fluid resuscitation and maintenance.

## **Why the Correct Answer is Right**
Ringer's lactate solution contains sodium (Na+), potassium (K+), calcium (Ca2+), and lactate ions. The standard composition of Ringer's lactate solution is: Na+ 130 mEq/L, K+ 4 mEq/L, Ca2+ 2 mEq/L, and lactate 28 mEq/L. Therefore, the correct answer is the option that matches 130 mEq/L of Na+.

## **Why Each Wrong Option is Incorrect**
- **Option A:** If the value is not 130 mEq/L, it does not match the standard composition of Ringer's lactate.
- **Option B:** Similarly, if the value does not align with 130 mEq/L, it is incorrect.
- **Option D:** This option also does not match the correct concentration of Na+ in Ringer's lactate.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that Ringer's lactate solution has a sodium concentration of 130 mEq/L, which is close to but slightly lower than that of normal saline (which has 154 mEq/L of Na+). This makes Ringer's lactate a more physiologically balanced choice for fluid resuscitation.

## **Correct Answer:** . 130 mEq/L