2. What set early humans apart from earlier hominids?

Explanation:

It is now understood that while there were considerable anatomical differences between the early hominins, they also shared a number of important traits. By 3 million years ago, most of them probably were nearly as efficient at bipedal locomotion as humans. Like people, but unlike apes, the bones of their pelvis, or hip region, were shortened from top to bottom and bowl-shaped (shown below). This made the pelvis more stable for weight support when standing upright or moving bipedally. The longer ape pelvis is adapted for quadrupedal locomotion. Early hominin leg and foot bones were also much more similar to ours than to those of apes. This is consistent with the likelihood of early hominin bipedalism.

your answer would be (b)