单项选择题
A.90%-98% B.80%-98% C.75%-90% D.65%-80%
A.75%-90% B.65%-80% C.60%-75% D.50%-65%
A.贫煤、瘦煤、焦煤、肥煤、气煤、不粘煤及长焰煤 B.贫煤、瘦煤、焦煤、肥煤、气煤、弱粘煤、不粘煤及长焰煤 C.贫煤、瘦煤、焦煤、肥煤、气煤 D.瘦煤、焦煤、肥煤、气煤、不粘煤