Which of the following policies did not apply to acequias?
a.
a farmer could block the water if he needed more.
b.
livestock was not allowed to spoil the water.
c.
bridges were constructed over the ditches.
d.
people were not allowed to waste water.

a. A farmer could block the water if he needed more.

Explanation:

Acequias are open-cast ditches or channels built for water irrigation, supply or similar purposes. Developed in Arab culture, these constructions have similar uses to Roman aqueducts. They are  mainly used to water gardens, crops or agricultural holdings, taking advantage of the terrain for water distribution and supply, creating a network of branches that derive from the main acequia. This makes them available for the inhabitants of a place, and if a farmer decides to block the water he would affect his neighbours' access to the acequias.

i believe your answer is d)