Under what specific circumstance is passing on the right (adelantamiento por la derecha) exceptionally permitted under Article 42 of Ley 24.449?

1. Whenever the vehicle ahead is traveling 10 km/h below the maximum speed limit
2. When the vehicle ahead is actively signaling its intention to make a left turn or has stopped to turn left
3. Whenever traveling on a rural expressway at night
4. Whenever driving a motorcycle with an engine under 250 cc