When another vehicle activates its left turn signal and begins overtaking your vehicle, what is the proper civilized driving response?

1. Accelerate immediately to prevent the other vehicle from passing
2. Swerve to the left to block the overtaking lane
3. Maintain a steady course, decelerate slightly if conditions require, and assist the passing vehicle in completing the maneuver safely (减速靠右让行)
4. Honk continuously and flash high beams to express disapproval