**Core Concept**
Pelvimetry is a radiological assessment of the pelvic dimensions to evaluate its suitability for vaginal delivery. It is crucial in obstetrics to predict potential difficulties during labor and delivery. Pelvimetry involves assessing various pelvic parameters, including the inlet, mid-pelvis, and outlet.

**Why the Correct Answer is Right**
Pelvimetry is indicated when there is a suspicion of cephalopelvic disproportion (CPD), which occurs when the baby's head is too large to pass through the mother's pelvis. This condition can lead to prolonged labor, fetal distress, or even cesarean delivery. X-ray pelvimetry helps obstetricians to assess the pelvic dimensions and identify potential issues.

**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because X-ray pelvimetry is not indicated in a normal pregnancy where there are no concerns about fetal size or pelvic dimensions.
* **Option B:** Incorrect because while X-ray pelvimetry may be used in cases of suspected CPD, it is not the sole indication. Other factors, such as fetal position and station, also play a crucial role in determining the need for a cesarean delivery.
* **Option C:** Incorrect because X-ray pelvimetry is not a routine assessment in all pregnancies. It is typically reserved for cases where there are specific concerns about fetal size or pelvic dimensions.

**Clinical Pearl / High-Yield Fact**
It is essential to note that X-ray pelvimetry has largely been replaced by other modalities, such as ultrasound and MRI, due to concerns about radiation exposure. However, it remains a useful tool in specific situations where other imaging modalities are not available.

**Correct Answer: A. Normal pregnancy.**