What Factor Is Associated with the Shift Away from Big

What factor is associated with the shift away from big game hunting in the temperate latitudes?

A) the development of new technology which allowed them to more efficiently process other resources
B) climate changes which resulted in many former prey animals going extinct or becoming geographically unavailable
C) a decline in human population caused by the environmental shifts made big-game hunting difficult
D) human over-hunting reduced the populations
E) a smaller range of potentially edible species were exploited