Concept:Tank irrigation and well irrigation are negatively related because they thrive in opposite geographic and hydrological conditions.
Explanation:Tank irrigation is common in areas with hard, impervious rock layers (like parts of Peninsular India) where rainwater cannot percolate deep.
These surfaces allow water to collect in tanks instead of recharging groundwater.
Well irrigation, on the other hand, depends on sufficient groundwater reserves, which are scarce in such impervious regions.
Thus, regions with many tanks have few wells, creating a negative spatial correlation.
Statement 2 correctly identifies that tank irrigation occurs where surface layers are impervious.
Statement 3 correctly notes that well irrigation needs adequate groundwater, which is absent in tank-irrigated areas.
Statement 1 (historical precedence) does not explain the present negative relationship, and statement 4 is too vague and not always true.
Answer:B. 2 and 3 only