The labels robustus, boisei, and aethiopicus refer to which of the following?
1) Hominins belonging to the Paranthropus grouping, representing approximately 3.5 million years ago to 1 million years ago.
2) Hominins belonging to the Australopithecines grouping, representing approximately 4.2 million years ago to 1.8 million years ago.
3) Hominins belonging to the Late Homo grouping, representing approximately 250,000 years ago to present day.
4) Hominins belonging to the Early Contender grouping, representing approximately 7 million years ago to 4.4 million years ago.