The correct answer is A. 1 in 30.
Camber is the slope of a road from the center to the sides. It is designed to help water drain off the road and prevent it from pooling in the middle. The recommended value of camber for water bound macadam roads in localities of heavy rainfall is 1 in 30. This means that for every 30 feet of road, the road should be 1 foot higher at the center than at the sides.
Camber is important for safety and for the longevity of the road. Without camber, water would pool in the middle of the road, making it difficult for cars to drive on and increasing the risk of hydroplaning. Camber also helps to prevent the road from becoming rutted and damaged.
The other options are incorrect because they are not the recommended value of camber for water bound macadam roads in localities of heavy rainfall.