When are roads most slippery during rain?

Answer: B — When it first starts raining

The answer is when it first starts raining because this is typically when roads become the most slippery. Initially, rain mixes with the oil and dirt that have accumulated on the road surface, creating a particularly slick condition. This mixture can cause reduced traction for vehicles, making it more dangerous to drive. As it continues to rain, the water can wash away some of the oil and dirt, leading to less slippery conditions than those found right at the onset of the rain. While heavy rain can lead to other hazards, like hydroplaning, it does not create that initial slickness that occurs when rain first begins to fall. Similarly, during a light drizzle, the effect on the road surface may not be as pronounced as during that very first moment of rain when the road is still saturated with oils and dirt.