Which of the Following Is/are Evidence of Robust Australopiths' Adaptation

Which of the following is/are evidence of robust australopiths' adaptation to eating hard-shelled seeds and grasses?

A) the presence of very large molars and a sagittal crest on the top of the skull
B) massive fossilized temporalis muscles
C) fine finger bones and a large mandible
D) a small but flexible masseter muscle and an enlarged occipital bun
E) bipedalism, providing the mobility necessary to gather food in open grasslands