Which of the following marks indicates you can pass if the way is clear?

A broken line indicates that passing is allowed if it is safe to do so. This marking suggests that the lane is open for drivers to move into the opposing lane to overtake another vehicle, provided they have assessed the situation and found that the way is clear. It strikes a balance by allowing for necessary maneuvers while still conveying that caution is required.

In contrast, solid lines indicate that passing is prohibited; they are used to prevent drivers from crossing into oncoming traffic areas. Double solid lines reinforce this restriction, clearly signaling that it is unsafe to pass at that location, while a "no passing zone" sign explicitly states that passing is not permitted in the designated area. Therefore, the broken line is the correct mark that allows passing under the right conditions.