**Core Concept**
Parkinson's disease is a neurodegenerative disorder characterized by tremors, rigidity, bradykinesia (reduced mobility), and postural instability. It is primarily caused by the depletion of dopamine-producing neurons in the substantia nigra pars compacta.

**Why the Correct Answer is Right**
The pathophysiology of Parkinson's disease involves the degeneration of dopamine-producing neurons, leading to a decrease in dopamine levels in the striatum. Levodopa, a precursor to dopamine, is converted into dopamine in the brain, thereby increasing dopamine levels and alleviating symptoms. This mechanism is the basis for the effectiveness of levodopa in treating Parkinson's disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not address the pathophysiology of Parkinson's disease. The treatment of Parkinson's disease is focused on increasing dopamine levels, not blocking its receptors.
**Option B:** This option is incorrect because it does not specifically target the underlying cause of Parkinson's disease. While anticholinergics may provide some relief, they do not address the root cause of the disease.
**Option C:** This option is incorrect because it is not a first-line treatment for Parkinson's disease. While it may provide some relief, it is not as effective as levodopa.

**Clinical Pearl / High-Yield Fact**
The cardinal symptoms of Parkinson's disease are tremors, rigidity, bradykinesia, and postural instability. The effectiveness of levodopa in treating Parkinson's disease is due to its ability to increase dopamine levels in the brain, thereby alleviating symptoms.

**Correct Answer: C. Dopamine agonists can be used but first line is Levodopa/Carbidopa combination.