Under Ministry of Transport standard JT/T 1240-2019, what is the purpose and structural requirement of the driver safety protective partition (城市公共汽电车驾驶区防护隔离设施) installed on city buses?

1. To provide a physical protective barrier around the driver's cockpit that prevents unauthorized passenger intrusion and physical assault while maintaining forward visibility, communication, and climate circulation
2. To completely soundproof the driver so they cannot hear passenger requests
3. To store heavy tools and passenger luggage around the driver's feet
4. To prevent the driver from looking in the rearview mirrors