## Core Concept
Long-term Levodopa therapy is a cornerstone in the management of Parkinson's disease, aiming to alleviate motor symptoms by increasing dopamine levels in the brain. However, chronic use of Levodopa is associated with several complications.

## Why the Correct Answer is Right
The correct answer involves understanding the complications associated with long-term Levodopa therapy. One of the significant issues with prolonged Levodopa use is the development of motor fluctuations and dyskinesias. Motor fluctuations refer to the variability in response to Levodopa, leading to a "wearing-off" effect where the drug's efficacy decreases towards the end of the dosing interval. Dyskinesias are involuntary, choreoathetoid movements that can occur as a result of long-term Levodopa therapy. These complications arise due to the pulsatile stimulation of dopamine receptors, which is different from the continuous dopamine release that occurs naturally.

## Why Each Wrong Option is Incorrect
- **Option A:** This option might suggest a benefit or a non-specific effect, which does not align with the known complications of long-term Levodopa therapy.
- **Option B:** Similar to Option A, this might propose an incorrect or unrelated effect, not directly linked to the recognized complications of chronic Levodopa use.
- **Option C:** This could potentially list a side effect not directly associated with long-term Levodopa therapy or might not fully capture the spectrum of complications.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that the introduction of Levodopa/carbidopa should be gradual to minimize side effects, and strategies to manage long-term complications include adjusting dosing intervals, adding dopamine agonists, MAO-B inhibitors, or COMT inhibitors, and considering deep brain stimulation in severe cases.

## Correct Answer Line
**Correct Answer: D.**