Which is _____ country,Canada or Australia?A.a large B.larger C.a larger D.the larger

Which is _____ country,Canada or Australia?A.a large B.larger C.a larger D.the larger
谁能给我这几个问题的答案并说出为什么?
1.Which is _____ country,CanadaorAustralia?
A.a large B.larger C.a larger D.the larger
2.Which of those radios sounds ____?– The smallest one.
A .good B.well C.better D.best
3.The number of giant pandas is getting ____ ,because their living areas are becoming farmlands.A .less and less B.larger and larger C.smaller and smaller D.fewer and fewer
4.He never does his work ____ Mary.
A .as careful as B.so carefully as C.as carefully as D.carefully