Which of these actions is a sustainable agricultural practice

a. cultivating crops that require less water
b. feeding a large population with factory farming
c. using water from another region to irrigate crops
d. using groundwater to irrigate crops

A. Cultivating crops that require less water

Explanation:

A sustainable agriculture practice is one that reduced the impact of that human activity on the environment.

A. Cultivating crops that require less water is certainly one sustainable practice because it respects the environment.

B, C and D answers are NOT sustainable practices and put in danger the reserves of water people will need to drink.  On top of that, B and C would generate pollution for the transport.