The correct options are
A Major rivers flow in south-west region of the country.
B The central and western part of Australia receives very less amount of rainfall.
D Because around 75% of the land is deserted.
Fishing is the major source of occupation, but it cannot be said to be the staple diet of all Australian people. Murray and Darling river fulfills the water need of highly populated south-west region of Australia. Australia consists of around 18% desert area. Also, a majot part of central and western Australia comprises arid and semi-arid regions. These regions very less rainfall, and thus are not suitable for habitation.