**Core Concept**
The basal ganglia are a group of subcortical structures involved in movement control, cognition, and reward-based learning. Parkinsonism is a clinical syndrome characterized by tremors, rigidity, bradykinesia, and postural instability, primarily due to the degeneration of dopaminergic neurons in the substantia nigra.

**Why the Correct Answer is Right**
The substantia nigra pars compacta (SNpc) is the primary component of the basal ganglia involved in Parkinson's disease. It is the site of dopaminergic neuron degeneration, leading to reduced dopamine synthesis and release in the striatum. This disruption of dopamine signaling in the basal ganglia circuitry causes the characteristic motor symptoms of Parkinsonism, including tremors, rigidity, and bradykinesia. The SNpc's dopaminergic neurons project to the striatum, where they regulate the activity of medium spiny neurons, which in turn modulate the activity of the globus pallidus and substantia nigra pars reticulata.

**Why Each Wrong Option is Incorrect**
**Option A:** The caudate nucleus is a component of the basal ganglia involved in cognitive and motor function, but it is not the primary site of dopaminergic neuron degeneration in Parkinsonism.
**Option B:** The putamen is a component of the basal ganglia involved in motor function, but it is not primarily involved in Parkinsonism.
**Option C:** The globus pallidus is a component of the basal ganglia involved in motor function, but it is not the primary site of dopaminergic neuron degeneration in Parkinsonism.

**Clinical Pearl / High-Yield Fact**
The substantia nigra pars compacta is the primary site of dopaminergic neuron degeneration in Parkinson's disease, leading to reduced dopamine synthesis and release in the striatum, which causes the characteristic motor symptoms of Parkinsonism.

**Correct Answer:** C.