**Core Concept**
The question is testing the understanding of the normal uterine contraction pressure, a critical parameter in obstetrics. Uterine contractions during labor are essential for fetal delivery, and their pressure is a key indicator of normal or abnormal labor progression.

**Why the Correct Answer is Right**
The correct unit is the Montevideo unit (MU), which is a measure of the intensity of uterine contractions. It is calculated as the product of the peak contraction pressure and the frequency of contractions. The Montevideo unit is used to assess the efficacy of uterine contractions, with normal values ranging from 200 to 300 MU. This measure is essential in obstetrics to diagnose and manage abnormal labor, such as uterine inertia or hypertonus.

**Why Each Wrong Option is Incorrect**
* **Option A:** The unit "mmHg" refers to millimeters of mercury, a measure of blood pressure. While uterine contractions do exert a pressure, mmHg is not the standard unit used to express this pressure in obstetrics.
* **Option B:** The unit "kg/cm²" is a measure of pressure, but it is not commonly used in obstetrics to describe uterine contraction pressure.
* **Option C:** The unit "g/cm²" is also a measure of pressure, but it is not the standard unit used to express uterine contraction pressure in clinical practice.

**Clinical Pearl / High-Yield Fact**
To remember the correct unit, recall that Montevideo units are calculated by multiplying the peak contraction pressure by the frequency of contractions. This calculation helps assess the efficacy of uterine contractions and diagnose abnormal labor.

**Correct Answer:** C. Montevideo unit