The correct options are
B Humans might never have begun cooking their food.
D Caves could have been a common option for permanent settlement across the globe.
A world without a man-made environment sounds like such an impossibility! However, if we were to take an educated guess, humans would probably have been limited to only living in hunter-gatherer societies across the globe. Naturally-occurring caves could have served as a common means for a permanent shelter. The cooking of food may never have become as common as it is in this day and age.