What is the primary purpose of setting 'toe-in' on the front wheels of a rear-wheel drive passenger vehicle?

1. To reduce the turning radius of the vehicle during low-speed parking maneuvers.
2. To offset the natural tendency of the front wheels to spread outward (toe-out) due to rolling resistance and compliance, ensuring parallel rolling at speed.
3. To increase the caster angle automatically at high highway speeds.
4. To prevent body roll during high-speed cornering.