The correct answer is - C. forestry and agriculture.
South and Southeast Asia are two regions considered to be developing regions, in general, though parts of them are very poor and are not in that faze. In order to achieve economic progress, not a lot of attention is focused on the environment and its preservation.
The deforestation is one of the biggest environmental problems. It happens very quickly, and it is happening due to the agriculture and the forestry. The agriculture needs more and more arable land, and in order to come to such a land, the forests are cleared and destroyed. Also, these regions have very high quality timber, so lot of it cut down and sold, which contibutes to the destruction of the forests.