SAT English Practice Question

In the 1960s, a group of scientists in the United States developed a new method for producing aluminum, but it was not clear what the environmental implications of the method were. Some scientists worried that the new method would release toxic chemicals into the environment, while others believed that the method would be safer than the previous methods. The new method was eventually adopted by the aluminum industry, and its environmental effects have been studied extensively since then. Based on the passage, which of the following claims is best supported by the text?

1. A.Scientists had no concerns about the environmental effects of the new method for producing aluminum.
2. B.The environmental effects of the new method for producing aluminum were clear from the start.
3. C.The environmental effects of the new method for producing aluminum were studied extensively before the method was adopted by the aluminum industry.
4. D.The environmental effects of the new method for producing aluminum were not fully understood until after the method was adopted by the aluminum industry.