Answer (B) is incorrect because the passage does not tell us that noxious ozone is formed in factories. From the information provided, all we know is that noxious ozone is formed in the troposphere. While possible that it is also formed in factories, that inference can't be drawn directly from what we are given.
Answer (E) is correct because it summarizes the passage. The first sentence tells us that using clean coal technology will result in a reduction of polluting emissions. Then the last sentence tells us that this reduction will lead to less noxious ozone formed in the troposphere. This sentence simply combines these ideas.
