For this question, A) does not question the validity of the premise. The premise says: importing oil on tankers PRESENTLY entails an even greater such risk per barrel of oil. A) says: Tankers CAN easily be redesigned so that their use entails less risk of an oil spill. CAN indicates a possibility IN THE FUTURE to reduce risk of tankers. Further, A) confirms that the PRESENT risk of using tank has risk of an oil spill. Therefore, A) accepts the premise, but presents a possibility to attack the CONCLUSION: Offshore drilling is better than tanker in terms of reducing risk. -- by 会员 sdcar2010 (2012/3/10 22:03:29)
nice explain . thx |