**Core Concept**
The failure to pass meconium within 48 hours of birth can indicate intestinal obstruction. **Hirschsprung's disease** is a common cause, characterized by the absence of ganglion cells in the distal bowel.

**Why the Correct Answer is Right**
Although the options are not provided, the diagnostic procedure of choice for a newborn who has not passed meconium involves assessing for intestinal obstruction. This typically starts with a **plain abdominal X-ray** to look for signs of obstruction, followed by more specific tests like a **rectal biopsy** to diagnose Hirschsprung's disease.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option, we can infer that any option not involving initial imaging or diagnostic tests for intestinal obstruction would be incorrect.
**Option B:** Similarly, any option not focused on diagnosing the cause of the obstruction, such as **Hirschsprung's disease**, would be incorrect.
**Option C:** An option that does not involve assessing the rectal ganglion cells or the intestinal patency would be incorrect.
**Option D:** An option that suggests a more invasive procedure without initial diagnostic workup would be incorrect.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the failure to pass meconium within the first 48 hours of life is a significant red flag for **Hirschsprung's disease**, and prompt diagnosis is crucial for management.

**Correct Answer:** D. Abdominal X-ray