Task: Question Answering
Input (English): Several species of fish live in a classroom aquarium. Students notice that the gills of one type of fish move faster than the gills of the other fish. Which of these statements is the best hypothesis on this observation?  
 (A) Fish have a two-chambered heart. (B) Some fish are much larger than others. (C) Fish need different amounts of oxygen. (D) There are six types of fish in the aquarium.
Output (English): C