Final answer:
Solid double yellow lines that are two or more feet apart may never be crossed; they indicate a no-passing zone and it is illegal to pass or make a U-turn across these lines.
Step-by-step explanation:
The correct answer is C. Solid double yellow lines that are two or more feet apart may never be crossed.
These lines are used to indicate a no-passing zone, meaning it is illegal to pass other vehicles or make a U-turn across these lines.
Violating these road markings can result in serious fines and penalties as it poses a risk to the safety of everyone on the road.