How Does Homo Erectus Differ from Homo Ergaster

How does Homo erectus differ from Homo ergaster?

A) H. erectus evolved into H. ergaster and was supplanted by H. ergaster.
B) The fossils looks very similar but H. erectus is an Asian form and H. ergaster is the African form.
C) H. erectus essentially looks like modern humans while H. ergaster is very apelike.
D) H. erectus and H. ergaster are identical except that H. erectus had tools and fire and H. ergaster did not.
E) H. erectus walked upright whle H. ergaster still walked on all fours.