Stanley Said:

English...?

We Answered:

Based on having had two books and dozens of articles published, I would say choice 4 is correct. (1) You, the reader, do not live in a hunting & gathering culture, so the word you is inappropriate. (2) Very true. (3) In general, specifying who is doing the action, rather than a hazy "you" or "one" or "some people" is to be preferred. Perhaps, "In early human societies, the people had either to hunt or gather plants for their food."