According to the Text, What Is a Carbon Footprint

According to the text, what is a carbon footprint?

A) a method for identifying and keeping track of behaviours that negatively impact the environment through greenhouse gas production
B) an estimate for gauging how much land and water area a human population requires to produce the resources it consumes and to absorb its wastes
C) a method for identifying and keeping track of the waste (regardless of its source) that negatively impacts society
D) an estimate of how much waste is added to landfill sites each year, based on garbage collection and landfill studies