One Hundred and Forty-Five Nations Share River Systems for at Least

One hundred and forty-five nations share river systems for at least some of their fresh water. According to the text, this situation:

A) Pressures nations to cooperate and thus reduces the likelihood of war
B) Has led the United Nations to develop guidelines for how much water each country can take from a shared water source
C) Has led to tensions between countries and sometimes to war
D) Has usually been resolved by private companies who claim ownership of the water and offer to sell it to the country willing to offer the most money for it