单项选择题

A big difference between Kojo and Sorie was that ______.

A.Kojo took chemicals for some useful experiment but Sorie only wasted his in making an alcoholic drink.
B.Sorie was rich but Kojo was poor
C.Kojo had a guilty conscience but Sorie did not
D.when Kojo objected, Sorie proved that what they were doing was reasonable