When is the road surface generally most slippery?

Answer: C — During the first few minutes of rain

The road surface is generally most slippery during the first few minutes of rain. This is because the initial rainfall mixes with oil and debris that have accumulated on the road surface over time. When rain begins to fall, it lifts these substances to the surface, creating a slick and potentially hazardous layer. As the rain continues, the water helps to wash away some of this oil and debris, reducing the slipperiness of the road. Understanding this can help drivers exercise extra caution during the early moments of rainfall, as the risk of slipping or losing traction is heightened during that period.