***20 ! *** today, land in urban areas typically is used for housing, transportation, and other structures, rather than for agriculture, primarily due to a. advancements being made in irrigation techniques b. fewer americans engaging in agriculture c. people relying more on other areas of the economy d. transportation time and shipping costs being reduced

I would go with answer choice D. transportation time and shipping costs being reduced

C

There are some close ones here. If you were writing an essay, you could talk about A B C and D. That's all of them! I don't think I've ever run across that before.

So you are going to have to narrow it down somehow.

A: really results in more efficient ways of producing crops. The number of acres available to get the same crop is reduced thus allowing for diversity in what is grown. It frees people up to do other things when production is increased by mechanical means.

B: might actually be the answer. You have to wait to see if there is anything better.

C: Since fewer people are needed for agriculture, people can make their living elsewhere, as in manufacturing.

D: Transportation and shipping cost reductions are important. Russia has not quite solved that problem yet and much of the produce from their huge  farms (50 sections) have rotted because they can't get their produce to urban markets.

Since this is an MC question, all the detail I have provided may not help you choose, but A and D make agriculture more efficient. So the choice is between B and C.

I think because B is true, C is the result. I would pick C, but don't be surprised if the answer is B