Read the following article and select the best answer. Article: The next great land area that man hopes to control is the moon. In size it is nearly equal to the area of North and South America. However, it presents a hostile environment. Temperatures range +120 to -150 degrees Centigrade. There is no air, and no water. Today there is considerable scientific speculation about living on the moon. When man will begin life on the moon surface is still not determined. But experts believe that settlement will take place in three steps. First, there will be increasing periods of exploration with temporary shelters. These periods will be followed by longer stays with housing under the surface of the moon and daily necessities brought by the settlers themselves from the earth. Finally, settlements that are self-supporting will be founded. The main job of the early settlers will be to stay alive. They will have to plant crops under huge domes to produce food and oxygen and find water sources. After this is done, the settlers will have time to explore the possibilities of commercial development and to make discoveries important to science. The characteristics of the moon that make it bad for human staying alive may make it ideal for certain kinds of manufacturing . Operations requiring a vacuum or extreme cold are examples. Therefore, industrial diamonds might be produced on the moon. Question: Though the environment on the moon is bad for human staying alive, it is very good for _ . - all kinds of manufactured goods - commercial development - making such things as industrial diamonds - medical operations
A:
making such things as industrial diamonds