Which adaption makes bipedalism possible

This is what bipedalism means:
Bipedalism refers to locomoting (e.g., walking, jogging, running, etc.) on 2 legs. It is not uncommon to see animals standing or walking on 2 legs, but only a few animals practice bipedalismas their usual means of locomotion.

So the adaption is the pelvis rotated inward.

Hope this helps!! :-)

The answer to this is b