**Core Concept**
The umbilical cord length is a key obstetric parameter that reflects normal fetal development and is clinically relevant for assessing cord complications like nuchal cord or cord compression.

**Why the Correct Answer is Right**
The average umbilical cord length in human fetuses ranges from **30 to 100 centimeters**, with most cords falling between 40–60 cm. This range is consistent across normal pregnancies and is influenced by fetal growth and maternal factors. A cord longer than 100 cm (especially >100 cm) may increase the risk of umbilical cord entanglement or compression, while a cord shorter than 30 cm may be associated with fetal growth restriction or complications. The measurement is typically taken from the internal opening of the fetal abdomen to the insertion point on the placenta.

**Why Each Wrong Option is Incorrect**
Option A: 40–50 cm – This range is too narrow and underestimates the normal variability; many cords exceed 50 cm.
Option B: 60–120 cm – This range is too long; cord lengths above 100 cm are rare and clinically concerning.
Option D: 25–40 cm – This range is too short and does not represent the full spectrum of normal cord lengths.

**Clinical Pearl / High-Yield Fact**
A cord length **>100 cm** is considered **long** and is associated with an increased risk of umbilical cord compression and fetal distress. Always assess cord length during obstetric exams to rule out complications.

✓ Correct Answer: C. 30-100 cms