Task: Question Answering
Input (English): Maria collected the gas given off by a glowing piece of charcoal. The gas was then bubbled through a small amount of colorless limewater. Part of Maria's report stated, "After the gas was put into the jar, the limewater gradually changed to a milky white color." This statement is  
 (A) an observation (B) a conclusion (C) a generalization (D) an assumption of the investigation (E) a hypothesis
Output (English): A