The map compares the present-day coastlines of Southeast Asia and Australia to their coastlines during the last ice age. A map titled Southeast Asia and Australia during the Last Ice Age. A key shows Present-day mainlands in light grey and Mainlands during the last ice age in grey. Grey surrounds southern Asia including most islands and Australia. The grey areas do not overlap.

Which statement does the map support about migration during the last ice age?

Early humans could migrate to Australia only by crossing a land bridge.
Early humans could migrate to Australia only by boat or other watercraft.
Early humans migrated from Southeast Asia to Australia by following herds of animals.
Early humans were prevented from migrating to Australia because sea levels were higher.