Match the following Column I with Column II.
`{:("Column I","Column II"),("A. Pollen grain","1. Photochemical smog"),("B. PAN","2. Particulate pollution"),("C. CO"_(2),"3. Global warming"),("D. Cadmium","4. Itai-itai disease"):}`
A. `{:(A,B,C,D),(2,1,3,4):}`
B. `{:(A,B,C,D),(4,2,1,3):}`
C. `{:(A,B,C,D),(1,2,3,4):}`
D. `{:(A,B,C,D),(3,1,2,4):}`
