Match the following Columns.
`{:("Column I","Column II"),("A. DDT","1. CO, CO"_(2)),("B. PAN","2. smog"),("C. Acid rain","3. Biological magnification"),("D. Global warming","4. SO"_(2)):}`
A. `{:("A","B","C","D"),(4,3,2,1):}`
B. `{:("A","B","C","D"),(1,2,3,4):}`
C. `{:("A","B","C","D"),(2,3,4,1):}`
D. `{:("A","B","C","D"),(3,2,4,1):}`
