Final answer:
The Australopithecines that were still in existence when the first individuals of the Genus Homo appeared include Australopithecus africanus. Hence the correct option is B.
Step-by-step explanation:
The Australopithecines that were still in existence when the first Genus Homo individuals appeared were Australopithecus afarensis. Australopithecus africanus is considered one of the species within the Australopithecus genus. The emergence of the Genus Homo, representing the early members of the human lineage, occurred around 2 to 2.4 million years ago. Australopithecus africanus coexisted with early members of the Homo genus during this transitional period. The other mentioned Australopithecine species, Australopithecus afarensis (option A), Australopithecus boisei (option C), and Australopithecus robustus (option D), were earlier forms of hominins that predated the appearance of the Genus Homo.