**Core Concept**
Pott's paraplegia, also known as Pott's paralysis, is a form of paraplegia resulting from **tuberculosis of the spine**. The prognosis of Pott's paraplegia depends on various factors, including the duration and progression of paraplegia.

**Why the Correct Answer is Right**
The correct answer is related to the factors that influence the outcome of Pott's paraplegia. **Acute onset** and **sudden progression** of paraplegia are generally associated with a poorer prognosis due to the rapid compression of the spinal cord. However, **long standing paraplegia** is also a poor prognostic factor as it indicates chronic damage to the spinal cord, reducing the chances of significant recovery.

**Why Each Wrong Option is Incorrect**
**Option A:** Acute onset of paraplegia is indeed a concern, but the question asks for poor prognostic factors, and the correct answer encompasses more than just the onset.
**Option B:** Sudden progression of paraplegia is similar to acute onset and is a concern, but again, not the most comprehensive answer.
**Option C:** Motor paralysis alone might not necessarily be a poor prognostic factor if it's the only symptom and if addressed promptly.
**Option E:** Paraplegia in children might have different prognostic factors compared to adults, but it's not the most direct answer to the question.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the prognosis of Pott's paraplegia is generally better with early diagnosis and treatment, especially if the paraplegia is of recent onset. Chronic cases or those with significant neurological deficit for a long period tend to have a poorer prognosis.

**Correct Answer:** D. Long standing paraplegia