**Core Concept**
Post-Streptococcal Glomerulonephritis (PSGN) is a type of kidney inflammation that occurs after an infection with group A beta-hemolytic streptococci (GABHS). This condition is characterized by the formation of immune complexes and the activation of the complement system, leading to glomerular injury and renal dysfunction.

**Why the Correct Answer is Right**
PSGN typically occurs 1-3 weeks after a streptococcal infection, such as pharyngitis or skin infections. The immune response to the streptococcal infection triggers the production of antibodies that bind to the glomerular basement membrane, causing inflammation and damage. The complement system is activated, leading to the formation of membrane attack complexes (MACs) that further damage the glomeruli. The involvement of the immune system and the complement pathway makes PSGN a classic example of an immune-mediated disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because PSGN is not primarily caused by a viral infection. While viral infections can trigger immune responses, PSGN is specifically associated with streptococcal infections.
**Option B:** This option is incorrect because PSGN is not a type of vasculitis. While vasculitis can cause inflammation and damage to blood vessels, PSGN is a specific type of glomerulonephritis that is triggered by an immune response to streptococcal infection.
**Option C:** This option is incorrect because PSGN is not a type of amyloidosis. Amyloidosis is a condition characterized by the deposition of abnormal proteins in various tissues, including the kidneys, but it is not related to PSGN.

**Clinical Pearl / High-Yield Fact**
PSGN can be differentiated from other types of glomerulonephritis by its association with a recent streptococcal infection and the presence of hematuria and proteinuria. A history of sore throat or skin infection in the weeks preceding renal symptoms should raise suspicion of PSGN.

**Correct Answer:** C.