单项选择题
A.2010 B.2020 C.2030 D.2035
A.3170元/吨,3180元/吨,3020元/吨 B.3220元/吨,3180元/吨,3040元/吨 C.3220元/吨,3260元/吨,3400元/吨 D.3270元/吨,3250元/吨,3100元/吨
A.8 B.-8 C.4 D.-4