A greenhouse is building where plants can be grown. It has walls that allow light and air inside. The amount of water and nutrients the plants receive can be controlled. Which is the best way for a farmer to make a greenhouse a good model for testing how crops will grow in a large field?

A)He could remove the walls of the greenhouse.

B) He could put windows around the field to make it like the greenhouse.

C)He could recreate the soil and water conditions of the field in the greenhouse.

D)He could place tiny models of farm equipment in the greenhouse.