Which of the following can be inferred from the passage concerning the relationship between traditional irrigation methods and modern ones
A． Traditional irrigation methods tend to come at a lower expense than more modern ones, which are generally dependent on technology.
B． Traditional methods may best be used in areas where the technological knowledge necessary for using modern techniques is limited.
C． Modern methods, unlike traditional ones, can only help land whose primary water source comes from irrigation, not rainfall.
D． Modern methods rely more heavily upon groundwater tapping, which itself depletes the aquifer.
E． Traditional methods can be performed without the tedious and difficult calculation of climate factors.