Critical Reasoning (CR) | Re: The overall operating costs of many small farms are reduced when the

The answer is B.
We can solve this question using the

Precise

approach, as there is enough information to figure out the answer by ourselves.
The passage argues that since a technique (using double the manure, rotating crops)is good for small farms, it will also be good for large farms.This assumes, among other things, that the large farms have the means to implement this technique : that they have the equipment to rotate the crops, and also -(B) that they have enough manure.