**Core Concept**
Primary amyloidosis, also known as AL amyloidosis, is a condition characterized by the deposition of abnormal light chain proteins in various tissues, including the nervous system. This deposition leads to disruption of normal tissue function, resulting in a range of clinical manifestations. The neurologic findings in primary amyloidosis are a result of the deposition of amyloid in the peripheral nerves, leading to peripheral neuropathy.

**Why the Correct Answer is Right**
The characteristic neurologic finding in primary amyloidosis is peripheral neuropathy, manifesting as a symmetric, length-dependent, sensorimotor neuropathy. This is due to the deposition of amyloid in the peripheral nerves, particularly in the nerve roots and the peripheral nerve trunks. The amyloid deposition disrupts the normal structure and function of the nerves, leading to symptoms such as numbness, tingling, and weakness in the extremities. The autonomic nervous system can also be affected, leading to orthostatic hypotension and other autonomic dysfunction.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because primary amyloidosis is not typically associated with a specific type of neuropathy, such as Guillain-Barré syndrome. While Guillain-Barré syndrome is a form of peripheral neuropathy, it is an autoimmune disorder and not related to amyloid deposition.

**Option B:** This option is incorrect because primary amyloidosis is not typically associated with seizures or other central nervous system manifestations. While central nervous system involvement can occur in other forms of amyloidosis, such as transthyretin amyloidosis, it is not characteristic of primary amyloidosis.

**Option C:** This option is incorrect because primary amyloidosis is not typically associated with a specific type of neuropathy, such as Charcot-Marie-Tooth disease. While Charcot-Marie-Tooth disease is a form of peripheral neuropathy, it is a genetic disorder and not related to amyloid deposition.

**Option D:** This option is incorrect because primary amyloidosis is not typically associated with a specific type of neuropathy, such as diabetic neuropathy. While diabetic neuropathy is a form of peripheral neuropathy, it is related to diabetes mellitus and not amyloid deposition.

**Clinical Pearl / High-Yield Fact**
A key feature of primary amyloidosis is the presence of a serum monoclonal protein (M-protein) on serum protein electrophoresis (SPEP) or urine protein electrophoresis (UPEP). The presence of a monoclonal protein is a hallmark of primary amyloidosis and is often used as a diagnostic criterion.

**Correct Answer:** C.