On the road you are traveling, the pavement markings change from broken white lines to solid white lines between the lanes of traffic. what does the line change mean?

When approaching an emergency vehicle, law enforcement vehicle, or tow truck stopped on a two-lane road with a speed limit of 20 mph or less, you are required to a. slow down to 10 mph b. slow down to 5 mph c. stop and offer assistance d. pass the vehicle in an opposing lane, if safe