Research (Van Vugt & Samuelson, 1999) in Which Water Meters

Research (Van Vugt & Samuelson, 1999) in which water meters were installed in houses in one community, suggests that when people can monitor their own use of a scarce common resource, they may use less of that resource because

A) using less helps them save money.
B) they become concerned for the collective good.
C) people become competitive and vie to use less.
D) They won't use less; installing the meters makes everyone want to make sure they "get their fair share," and use goes up.