One way that Australopithecus differed from apes was that they walked upright on two feet. Option A is correct.
Australopithecus is a 'genus' of hominins. According to paleontological and archaeological evidence, the genus Australopithecus evolved in eastern Africa approximatelly 4 million years ago before expanding throughout the continent and becoming extinct two million years ago.
These extinct primates are closely related to modern human beings.
The most known specimen of Australopithecus is “Lucy,” a remarkably preserved fossilized skeleton from Ethiopia that has been dated to 3.2 mya.