Which of the following statements about lane sharing with another motorcycle is correct?

1. Two motorcycles may always ride side-by-side in a single lane on Arkansas highways
2. Two motorcycles may ride side-by-side in a single lane only with mutual agreement, and even then it is generally safer for them to ride in a staggered formation
3. Motorcycles must always single-file regardless of road or traffic
4. Lane sharing is only allowed at speeds under 10 mph