**Core Concept:** Streptokinase is a fibrinolytic agent used for the treatment of acute ischemic stroke due to cerebral arterial occlusion. It works by breaking down the fibrin clots in blood vessels, restoring blood flow and potentially reducing the risk of long-term disability or death.

**Why the Correct Answer is Right:** Streptokinase is administered as an intravenous bolus dose of 1.5 million units (150,000 IU) over 10-20 minutes. This dose is chosen based on the pharmacokinetics of streptokinase and its efficiency in dissolving blood clots.

**Why Each Wrong Option is Incorrect:**

A. **1 million units (100,000 IU)**: This dose is too low and may not effectively dissolve the clot.
B. **3 million units (300,000 IU)**: This dose is too high and carries a higher risk of side effects, such as bleeding complications.
C. **5 million units (500,000 IU)**: This dose is too high and carries a higher risk of side effects.

**Clinical Pearl:** In the treatment of acute ischemic stroke, the choice of streptokinase dose is crucial to balance the benefits of clot dissolution against the risks of bleeding complications. The optimal dose can vary based on the patient's individual characteristics and the severity of the stroke.

**Correct Answer:** . 1.5 million units (150,000 IU)