The correct answer is placing monetary values on everything
Activities such as a bonfire we do for fun we’re necessities in the past as they had no other way to keep warm or to heat food whilst we today just do it for fun to roast marshmallows and to get outside for a fun activity. But back then this was necessary for survival and the discovery of fire was one of the most influential things back in the past.
The answer is D because it still isn't a conscious thought