Final answer:
Obstruction markings guide drivers around obstructions in the road. White obstruction markings allow passing on either side, while yellow obstruction markings restrict passing on either side.
Step-by-step explanation:
Obstruction markings are solid lines painted in traffic lanes to guide drivers around obstructions in the road. White obstruction markings indicate that you may pass to either side of them, while yellow obstruction markings indicate that you may not pass on either side.
Therefore, the correct answer is option 4: None of the above.