Australia Shares Fossils and Extant Plant and Animal Taxa with Other

Australia shares fossils and extant plant and animal taxa with other continents, particularly Antarctica and South America. The most widely accepted explanation for this is that

A) many plants and animals were able to disperse the long distances to Australia over the oceans.
B) the separate continents were connected to Australia by land bridges, across which flora and fauna dispersed.
C) the continents were once joined together in a larger supercontinent across which the plants and animals were able to disperse.
D) dispersal of these species by land bridges.
E) these taxa evolved independently in the different continents.