**Core Concept**
Thrombolytic therapy involves the use of medications that activate plasminogen to plasmin, resulting in the breakdown of fibrin clots. This process is crucial in the management of acute ischemic stroke and myocardial infarction.

**Why the Correct Answer is Right**
The correct thrombolytic agent that leads to plasmin activation is streptokinase. It works by binding to plasminogen and converting it into plasmin, which then degrades fibrin clots. This action is mediated through the formation of a complex between streptokinase and plasminogen, resulting in the activation of plasminogen to plasmin. The subsequent breakdown of fibrin clots leads to the restoration of blood flow to the affected area.

**Why Each Wrong Option is Incorrect**
**Option A:** Alteplase is a different thrombolytic agent that works by directly activating plasminogen to plasmin, but it is not the correct answer in this context.
**Option B:** Urokinase is another thrombolytic agent that activates plasminogen to plasmin, but it is not the correct answer in this context.
**Option D:** Tissue plasminogen activator (tPA) is a thrombolytic agent that activates plasminogen to plasmin, but it is not the correct answer in this context.

**Clinical Pearl / High-Yield Fact**
Streptokinase is a bacterial-derived thrombolytic agent that has been widely used in the management of acute ischemic stroke and myocardial infarction. However, it is associated with a higher risk of allergic reactions and bleeding complications compared to other thrombolytic agents.

**Correct Answer: C. Streptokinase**