Task: Question Answering
Input (English): Many years ago, purple dye was made from some sea animals. Then, in 1856, William Perkins tried to make a new medicine. Instead, he found a way to make purple dye from coal. What is a positive effect of his discovery?  
 (A) Some diseases can be treated. (B) Purple clothing can be made. (C) Sea animals are not needed to make purple dye. (D) Perkins is famous for discovering a new medicine.
Output (English): C