**Core Concept**
Acquired megacolon refers to a condition where the colon becomes abnormally dilated due to a secondary cause, often resulting from a loss of normal motility. This can occur due to various factors, including neurological disorders, prolonged use of certain medications, or as a consequence of another underlying medical condition.

**Why the Correct Answer is Right**
The correct answer is seen in Hirschsprung's disease is incorrect because it is a congenital condition. Acquired megacolon can be seen in conditions like chronic intestinal pseudo-obstruction (CIPO), where there is a loss of normal motility in the colon. This can be due to a variety of causes, including neurological disorders such as Parkinson's disease or multiple system atrophy, or as a consequence of medications such as opioids or anticholinergics. In CIPO, the colon becomes dilated due to a lack of coordinated muscular contractions, leading to a buildup of fecal material and potential complications.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it is a congenital condition, not an acquired one.
* **Option B:** This option is incorrect because it is a condition where the colon is not dilated, but rather, there is a buildup of fecal material due to a mechanical obstruction.
* **Option D:** This option is incorrect because it is a condition where the colon is dilated, but it is a congenital condition, not an acquired one.

**Clinical Pearl / High-Yield Fact**
It is essential to differentiate between congenital and acquired megacolon, as the underlying causes and management strategies differ significantly. Acquired megacolon often requires a thorough evaluation to identify the underlying cause, whereas congenital conditions may require surgical intervention.

**Correct Answer:** C. Chronic intestinal pseudo-obstruction.