The road is most slippery a. after a long rain. b. when it is new. c. during the first half hour of the rain.

C. during the first half hour of the rain.

Explanation:

The first few minutes of rain are the most dangerous because the water mixes with the dirt and oil on the floor to form a narrowly slippery paste. After a good storm, the asphalt gets washed and the grip improves. In the city there are some traps hidden under the water. For example, the streams that have been channeled and that after a heavy rain overflow, ripping the manhole covers and wolf mouths. Whenever a rider finds a water-covered avenue, even at a shallow depth, it is advisable to change course or wait for the water to drain a little. to avoid an unpleasant surprise of feeling the ground disappear under the front wheel.