Though Many Islands of the Indonesian Archipelago Are Relative Close

Though many islands of the Indonesian archipelago are relative close to Australia,the faunal assemblages of these Indonesian islands are quite different from those on Australia.What accounts for the difference?

A) These Indonesian islands experienced a major extinction that wiped out its marsupials and other Australian fauna.
B) A deep ocean barrier inhibited dispersal between the two realms.
C) The environments of Australia and Indonesia are completely different,despite their close proximity.
D) Indonesia is an archipelago whereas Australia is a continent.As such,one would not expect them to have the same faunal assemblages.
E) Though once connected by a land bridge during the Last Glacial Maximum,rising sea levels with the glacial retreat led to different speciation events in the two realms.