单选题

　　[填句补文]Rough estimates in the past have predicted similarly disappointing results. ________ Says Sallie Chishol， an environmental engineer from the Massachusetts Institute of Technology. “But the take-home message is the same. Ocean fertilization is not the answer to global warming.”

　　A、“These are newer and better models，”

　　B、Its opponents argue， however， that it will stop global warming.

　　C、Adding iron to patches of ocean can make plankton bloom temporarily.

　　D、As plankton die and settle on the ocean floor， their carbon is supposedly locked up in the seabed.