Does mandatory gun ownership prevent crime? To study this, the number of burglaries committed each month in a small town were recorded for 75 months prior to passage of a bill requiring citizens to own guns and for 56 months after passage of the bill. The goal was to see if the number of burglaries committed was affected by requiring citizens to own guns. The response variable here is

A. The number of burglaries committed each month.
B. The passage of the bill requiring citizens to own guns.
C. The citizens' willingness to own guns.
D. The size of the small town.