Which of the following is not an agricultural technique?
a. irrigation
b. selective breeding
c. livestock herding
d. none of the above

The correct answer is option D

The agricultural technique can be defined as the techniques which is used in order to increase the crop production, animal husbandry, enhance the quality of food, et cetera.

The irrigation can be defined as the providing water to the plants that is grown for grain production.

Livestock herding and selective breeding are also considered as the agricultural practices including irrigation.

So, all of the above choices are agricultural techniques.

i believe it would be c: tons.