**Core Concept**
Fetal weight assessment is a critical component of prenatal care, allowing healthcare providers to predict gestational age, detect growth restriction, and monitor fetal well-being. This is typically achieved through a combination of clinical evaluation and sonographic measurements.

**Why the Correct Answer is Right**
Ultrasound assessment of fetal weight is based on the principle that the size of the fetus is directly correlated with gestational age. Fetal weight can be estimated using various sonographic parameters, including the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL). These measurements are then used to calculate the estimated fetal weight (EFW) using various formulas, such as the Hadlock formula.

**Why Each Wrong Option is Incorrect**
**Option A:** There is no widely accepted method for assessing fetal weight through maternal urine analysis. While urine analysis can provide information on fetal well-being, such as the presence of proteinuria or glucosuria, it is not a reliable method for estimating fetal weight.

**Option B:** Fetal weight cannot be accurately assessed through palpation alone. While a healthcare provider may be able to estimate fetal size through abdominal palpation, this method is subjective and not reliable for precise measurements.

**Option C:** Fetal weight cannot be directly measured through magnetic resonance imaging (MRI). While MRI can provide detailed images of the fetus, it is not typically used for fetal weight assessment due to its high cost and limited availability.

**Clinical Pearl / High-Yield Fact**
A commonly used formula for estimating fetal weight is the Hadlock formula, which takes into account the biparietal diameter, head circumference, abdominal circumference, and femur length to provide an accurate estimate of fetal weight.

**Correct Answer:** C. Ultrasound assessment.