Modern Humans, and Probably Homo Erectus, Have Much Shorter Intestines

Modern humans, and probably Homo erectus, have much shorter intestines than expected for primates of their size. What possible change in hominin technology may account for this?

A) increased hunting of easier-to-digest mammals, such as antelopes
B) the use of fire to process food
C) a shift from some hunting but mostly scavenging to mostly hunting
D) a reduction in food sharing, which also meant a reduction in food-borne diseases