Well it depends on what the answers are
however if we assume the answers are these:
A. Improved sanitation techniques reduce water pollution, which promotes water conservation.
B. Modern sanitation techniques create increasing amounts of water pollution, which hinders water conservation.
C. Communities that invest in sanitation techniques are less likely to invest in water conservation.
D. Communities cannot encourage water conservation without also developing sanitation techniques.
then I believe the answer would be A
Sorry if I got it wrong!