Task: Question Answering
Input (English): Scientists dig in a dry area at the bottom of a mountain range. Fossilized shells of freshwater mussels are found in the area. Which is a likely conclusion that scientists will draw based on this evidence?  
 (A) Rivers once flowed through the area. (B) Volcanoes were once active in the area. (C) The ocean shoreline once reached this area. (D) Floods were a common occurrence in this area.
Output (English): A