The correct option is C Retention of water and prevention of erosion
Forests helps in producing rainfall. More are the trees, the more water gets absorbed into clouds and the more it helps in rain falls. The roots of a tree make gaps in the soil so that when it rains the water can sink in before being absorbed by the soil. These spaces also allow air and water to reach the roots of the plants. If the forests disappear, there will be less rain resulting in dryer conditions, that eventually lead to drought. Once this happens, the damage is extensive making it difficult to plant more trees or plants later because the soil is so hard and dry. When trees removed using heavy machinery, the soil is pushed down and the gaps fill in. Because all plants and trees need that water and air to reach roots, the conditions become unfriendly for new growth.