**Core Concept**
Intestinal pseudo-obstruction refers to a condition where the bowel functions abnormally, mimicking the symptoms of a mechanical obstruction without any physical blockage. This condition is characterized by abnormal motility and failure of the intestinal muscles to propel food, fluids, and gas through the digestive tract.

**Why the Correct Answer is Right**
Intestinal pseudo-obstruction occurs due to abnormal smooth muscle function, often resulting from autonomic nervous system dysfunction or degeneration of the enteric nervous system. The condition can be idiopathic or secondary to various factors such as medications, metabolic disorders, or systemic diseases like scleroderma or amyloidosis. In this case, the patient's lack of bowel movements for 14 days, despite the absence of air-fluid levels on X-ray, suggests a non-mechanical cause of obstruction. The absence of air-fluid levels helps to rule out mechanical obstruction, where one would typically expect to see this sign.

**Why Each Wrong Option is Incorrect**
**Option A:** Paralytic ileus is a condition characterized by a complete cessation of intestinal motility, often due to surgical manipulation, electrolyte imbalances, or certain medications. However, paralytic ileus would typically present with air-fluid levels on X-ray, which is not seen in this case.

**Option B:** Aganglionosis of the colon, also known as Hirschsprung's disease, is a congenital condition characterized by the absence of ganglion cells in the distal colon. This condition typically presents in infancy or early childhood with chronic constipation and is not relevant to this adult patient.

**Option D:** Duodenal obstruction refers to a mechanical blockage of the duodenum, which can be caused by various factors such as gallstones, tumors, or external compression. The absence of air-fluid levels on X-ray and the patient's symptoms make this option less likely.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that intestinal pseudo-obstruction can mimic the symptoms of mechanical obstruction, making it crucial to investigate the cause of obstruction thoroughly, including the use of imaging studies and endoscopic evaluations.

**✓ Correct Answer: C. Intestinal pseudo-obstruction**