When passing another vehicle on a two-lane road, what is the speed limit?

Answer: B — 55 mph

Passing another vehicle on a two-lane road means that there is only one lane in each direction. In this scenario, the speed limit is typically 55 mph. Option A, 20 mph, is too slow for highway speeds and is often reserved for residential areas. Option C, 65 mph, and Option D, 75 mph, are both above the standard speed limit for this situation and would be considered speeding. Therefore, the correct answer is B, 55 mph.