What is scientists' attitude towards the future of Chad Lake

A．Chad Lake located in the middle of Chad in northern Africa.
B．The water from Chad water can now only be used for irrigation.
C．The area around Chad Lake has suffered from heavy rain lack many decades.
D．Population around the Chad Lake now begins to decrease due to water lack.

A．They broke down and the main parts turned into oxygen.
B．They broke down and the carbon content had mainly turned into carbon dioxide.
C．They broke down and the carbon content was mainly absorbed in the soil.
D．They absorbed more carbon dioxid